The Quantification of Migration
between Mexico and the United States
Frank D. Bean, Rodolfo Corona, Rodolfo Tuirán
& Karen A. Woodrow-Lafield
T
he migration of Mexicans to the United States is a complex phenomenon,
with a long history and structural roots on both sides of the border. Not
surprisingly, Mexico and the United States have often held dissimilar views
of this migration. On each side of the border, government officials, policy specialists
and the public have often revealed distinct perceptions as to the nature, magnitude,
causes and consequences of the movement of persons between the two nations.
This complicates the task of the analyst. This report seeks to simplify analysis by
focusing only on the question of the quantity of migration. How large is the flow
and what is the sizes of the populations in the two countries that result from it?
These are among the most often discussed aspects of migration, ones that lend
themselves to intense speculation. In Mexico and the United States, the question of
numbers arises frequently as part of the public debate on migration, and analyses
of the causes and impacts of migration in both countries depend, to a considerable
extent, on the calculations (well founded or not) about the size of the phenomenon.
One of the first conclusions of this report is that Mexican migrants to the United
States are not homogeneous, but rather consist of diverse subgroups that migrate
1
for different reasons (Bean, et al., 1994; Corona, 1993). Distinguishing among
migrants is necessary in order to demarcate flows conceptually and in order to
interpret the results of efforts to measure them. Recognizing differences among
migrants also helps to evaluate the impacts of migration on the societies of origin
and destination. From the outset, the question of the magnitude of immigration,
therefore, has facets that imply a number of subquestions. How many Mexicans
(authorized and unauthorized) are located at any given time in the United States?
Of these, how many habitually reside in that country? How many work or look for
work in the United States but actually live in Mexico? How many Mexicans enter
the United States annually to reside in that country or to work in it? How many
return within the same time period? What is the net flow, or the difference between
the total entries and the total return flows?
Researchers trying to answer such questions on international migration are
confronted with diverse methodological and technical problems. Besides the problems confronting efforts to quantify migratory flows that are well-known, other
problems arise from the special characteristics of the movement of Mexicans to
the United States. Analysis is difficult because of the surreptitious nature of much
of the flow, the constant change in the nature of migratory populations, the difficulties in determining how long Mexicans stay in the United States, and the difficulties in estimating the considerable size of return flows to Mexico (even after
lengthy periods of residency in the United States). This report seeks to overcome
these difficulties insofar as possible. Its two main objectives are (1) to assess the
results and adequacy of efforts of the past 25 years to estimate the magnitude of
migration between Mexico and the United States, and (2) to develop estimates of
the stocks and flows of migrants between the two countries circa the mid-1990s,
based on the approaches and results of earlier assessments as well as on newly
available data and research conducted in the 1990s.
Before proceeding further, two additional comments are in order. The first
concerns terminology. We use the term “unauthorized migrant” throughout this
report to refer to those Mexican migrants who are in the United States without
authorization at a given point in time, either because they have surreptitiously entered the country or because they overstayed their legally authorized periods of
stay. We are aware that many observers prefer other terms. Our choice of nomenclature is based on our conclusion that the term “unauthorized migrant” most accurately describes the category of persons who are not in the United States legally.
We use the term migrant rather than immigrant because many of the persons in this
category enter the United States for temporary purposes, that is they stay only
short periods of time.
The second matter concerns the consequences of the Immigration Reform and
Control Act (IRCA) of 1986 for Mexican migration flows. This legislation has had
2
such profound implications for the numbers and kinds of Mexican migrants going
back and forth between Mexico and the United States that we wish to signal and
underscore the importance of IRCA for our topic at the outset of this report. In
almost every one of our discussions, we will be noting not only the ways in which
we endeavor to measure the stocks and flows of migrants, but also the ways in
which IRCA has influenced their magnitude. And because IRCA’s legalization provisions have so increased the numbers of persons eligible for immigrant visas under the current provisions of U.S. immigration law, IRCA will also have implications for immigration flows in the future, as we note below.
The rest of this report is divided into six sections. We first consider the recent
sizes of the total Mexican-origin and Mexican-born populations in the United
States. Second, we discuss estimates of legal immigration from Mexico to the
United States. Third, we examine estimates of unauthorized migration to the United
States that are based mostly on U.S. data. Fourth, we present estimates of migration
from Mexico to the United States that are based on recent data collected in Mexico.
Fifth, we examine the available evidence about the migration to Mexico of persons
from the United States and other countries. Sixth, we summarize and synthesize
the results from the above sections, together with other recent data, to develop
what we think are reasonable numbers as to the magnitude of the stock and flows
of Mexican migrants to the United States just after the middle of the decade of
the 1990s.
The Total Mexican-origin Population
in the United States
The Mexican-origin population living in the United States has grown
substantially during the 20th Century. The population consists of several groups
with different experiences. First, there are those individuals born in the United
States who can trace their ancestry to Mexico. This group in turn consists of those
persons whose ancestors lived in those parts of the United States that once were
part of Mexico, as well as those persons whose ancestors migrated to the what is
now the United States. Second, there are those individuals born in Mexico who
have subsequently moved to the United States. This group in turn can be broken
down into three sub-groups—naturalized citizens, legal immigrants and
unauthorized migrants from Mexico. The following discussion examines the size
and growth of the total Mexican-origin population living in the United States,
focusing on changes in the size of each of these components where possible. Our
major purpose here is not to examine the estimates of these components in detail,
because we undertake that exercise below. Rather, it is to demonstrate the rough
size of the migration components in relation to the total. We begin by examining
3
changes in the way this group has been measured over time. Since the United
States Census is the primary source of this information, we focus first on changes
in census definitions. Then, we discuss the patterns of growth in the Mexicanorigin population over the past century.
“Ethnicity” denotes a social identity deriving from group membership based
on common race, religion, language, national origin, or some combination of these
factors (Bean and Tienda, 1987:38). In part because ethnicity is a multi-dimensional
concept, the way in which the Mexican-origin population has been defined by the
United States Census Bureau has changed over the years in part because
measurements have been based on a number of different indicators at different
points in time (see Table 1). Prior to 1970, Mexican ethnicity could be
operationalized through the use of various objective markers, including place of
birth, parents’ place of birth, language and Spanish surname. While serving to
identify well Mexican-origin persons who were either foreign born or whose parents
were born in Mexico, these identifiers failed to identify adequately third or higher
generation Mexican-origin persons, especially those who no longer spoke Spanish
at home or who no longer had a Spanish surname due to intermarriage. These
limitations were especially problematic for identifying the Mexican-origin
population given the group’s long history in the United States. In response to
Table 1
Identifiers Available in the United States Census or Current Population
Survey for the Hispanic Population, 1950-1996
Year
Birthplace
Foreign
Parentage
Mother
Tongue
1994-96
1990
1980
1970
1960
1950
yes
yes
yes
yes
yes
yes
yes
no
no
yes
yes
yes
no
no
no
yes
yes
no
2
Home
Language
Other than Spanish1
English Surname
no
yes
yes
no
no
no
no
no
yes
yes
yes
yes
Spanish
Origin
or
Descent
Ancestry
yes
yes
yes
yes
no
no
no
yes
yes
no
no
no
Source (1950–1980) Bean and Tienda, 1987; (1990 Census and 1994-96 CPS) Constructed
by the authors.
1
Only available for five southwestern states.
2
Available for 25% of the foreign-born population
4
these concerns, a new measure of ethnicity was added to the 1970 Census in which
Mexican ethnicity could be identified through the use of a subjective item, Spanish
origin. The census measure on Spanish origin allowed respondents of any
generation to identify themselves as possessing Mexican or several other Spanishorigin ethnicities.
Such changes in the basis for measuring the Mexican-origin population of the
United States do not mask the fact that the Mexican-origin population has grown
steadily over the last several decades (Table 2). Some of this growth can be attributed to natural increase in the U.S.-born Mexican-origin population. MexicanAmerican fertility rates are approximately 35 to 40 percent higher than those of
Anglos (Bean and Tienda, 1987; Bachu, 1995; Clark and Ventura, 1994), while
each of these groups appears to experience comparable mortality rates. Thus, even
in the absence of migration, the share the Mexican-origin population contributes to
Table 2
Total Mexican-origin Population in the United States: 1900-1996
Year
Total Mexicanorigin Population
(in Thousands)
Percent of
Total U.S. Population
1996
18,039 1
6.8
1990
13,393
5.4
1980
8,740
3.9
1970
4,532
2.2
2
1960
1,736
1950
1,346
0.9
1940
1,077
0.8
1930
1,423
1.2
1920
740
0.7
1910
385
0.4
1.0
Source: U.S. Immigration and Naturalization Service. Historical Statistics
of the United States, Part 1 (1975), U..S. Bureau of the Census, 1980 and
1990, and March Current Population Survey, 1995 and 1996.
1
These figures are based on CPS data that are adjusted for undercount
and thus are not comparable to census figures.
2
Mexican-origin population calculated as a sum of the Mexican-born
population and natives of Mexican parentage.
5
growth in the total population would increase relative to the share contributed by
the Anglo population.
The present day size of the Mexican-origin population in the United States,
however, is mostly attributable to immigration from Mexico during the 20th Century.
Corona (1994) and Edmonston and Passel (1994) estimate that the Mexican-origin
population in 1990 would only have been 12-14 percent of its current size had
there been no immigration from Mexico since 1900. Table 3 presents the size of
the Mexican-born population in the United States for each decade of the 20th Century.
The flow of immigrants from Mexico has fluctuated substantially throughout this
period, but it is clear that the Mexican-born population has become over time an
increasingly large component of the foreign-born population of the United States.
The growth of the Mexican-born population in the United States has varied as
a consequence of economic and political conditions on both sides of the border
Table 3
Total Mexican-born Population in the United States: 1900-1996
Year
Mexican-born
Population
(in Thousands)
Percent of the
Total Foreign-born
Percent of the
Total Mexicanorigin Population
1996
6,679 1
27.2
37.0
1990
4,298
21.7
32.1
1980
2,199
15.6
25.2
1970
759
7.9
16.7
1960
576 2
5.9
33.2
1950
454
4.4
33.7
1940
377
3.2
35.0
1930
617
4.3
43.4
1920
486
3.5
65.7
1910
222
1.6
57.7
1900
103
1.0
Source: U.S. Immigration and Naturalization Service. Historical Statistics of the United States,
Part 1 1975), U.S. Bureau of the Census. 1980 and 1990, and March Current Population
Survey, 1995 and 1996.
1
These figures are based on CPS data that are adjusted for undercount and thus are not
comparable to census figures.
2
Mexican-origin population calculated as a sum of the Mexican-born population and natives of
Mexican parentage.
6
(Freeman and Bean, 1997; Szekeley and de la Garza, 1997). The border between
Mexico and the United States attained its modern definition in 1848, but records
on the Mexican immigration to the United States were not kept until 1908. The
accuracy of such data is dubious, however, as the border region at that time was
largely unsupervised and the nature of immigration from Mexico at the very beginning of the 20th Century is unknown. Two of the border states (Arizona and New
Mexico) were only territories under U.S. supervision until 1912. The first large
scale officially measured immigration from Mexico into U.S. territory occurred
between 1910 and 1919. Increased demands for labor brought about by the exclusion of Chinese workers in 1882, Japanese workers in 1907 and a shortage of European immigrants during World War I encouraged Mexican migration. Numbers of Mexican migrants continued to increase as the federal government exempted
the Western Hemisphere from the national quota laws of the 1920s and early 1930s
in the name of Pan Americanism which was also encouraged by many in the southwest who looked towards Mexico for cheap labor (Reimers, 1992). However, when
the demand for labor decreased during the Great Depression of the 1930s, The
United States repatriated many Mexican-origin individuals. Many of those sent
involuntarily to Mexico were American-born children.
Levels of migration from Mexico once again increased with the introduction
of the Bracero Program from 1943-1964 (Figure 1). Starting in World War II,
non-Mexican farm workers in California sought higher paying jobs in the defense
Figure 1. Legal Immigrants Admitted from Mexico, Europe and Total, 1821-1994
7
industry, reducing the available labor supply for farmers. This prompted growers
to place pressure on Congress to admit temporary workers, or braceros, from
Mexico. During the peak of the program in 1956, the number of workers recruited
was 445,197 (Reimers, 1992). Although these workers were expected to be
temporary residents in the United States, many stayed along with their family
members. While growers fought to retain the supply of cheap Mexican labor,
Congress refused to extend the program beyond 1964.
Despite the end of the Bracero Program, both unauthorized and legal migration
from Mexico has continued to grow during the past three decades (Figure 2). In
particular, the size of the legal population increased dramatically during the late
1980s and early 1990s, in part due to the legalization provisions of the 1986
Immigration Reform and Control Act (IRCA). Between 1989 and 1994, IRCA offered
legal status to approximately 2 million undocumented Mexican migrants who had
been either working in agriculture or living illegally in the United States before
1982. Table 4 illustrates the effect of IRCA’s legalization programs on the size of
the flow of immigrants from Mexico. When those legalizing their status under the
amnesty provisions are removed from the official numbers of immigrants arriving
in the decade, the size of the Mexican migrant population entering between 1981
and 1994 is greatly reduced. Another segment of the Mexican-born population in
the United States is the unauthorized migrant population. We discuss below in
Figure 2. Legally Resident Foreign-born by Mexican Birth: 1970-1990
8
Table 4
Immigration from Mexico to the United States: 1900–1995
Years
Number Arriving
from Mexico
in the Decade
Percent of All
Immigrants Arriving
in the Decade
A. Published Totals
1991-1995
1981-1990
1971-1980
1961-1970
1951-1960
1941-1950
1931-1940
1921-1930
1911-1920
1901-1910
1,490,040
1,655,843
640,294
453,937
299,811
60,589
22,319
459,287
219,004
49,642
28.5
22.6
14.2
13.7
11.9
5.9
4.2
11.2
3.8
0.6
B. Numbers of Mexican Arrivals Excluding IRCA legalizations1
1991-1995
1981-1990
440,662
693,213
11.3
11.6
Source: U.S. Immigration and Naturalization Service, 1995 Statistical Yearbook of
the Immigration and Naturalization Service. U.S. Government Printing Office,
Washington, D.C., 1997.
1
Numbers of those legalizing their immigration status from the Statistical Yearbook
of the Immigration and Naturalization Service (1989–1995).
considerable detail estimates of the size of the unauthorized Mexican migrant
population and the methods used to arrive at these estimates
Another component of the Mexican-born population in the United States
includes those immigrants who have become citizens of the United States. Table 5
presents the numbers of Mexican-born persons who have naturalized over the past
35 years. Compared to other immigrant groups in the United States, Mexican
immigrants have been slow to naturalize (Grebler, 1966; Bean and Tienda, 1987).
English language ability is frequently cited as the largest barrier to citizenship
among Mexican immigrants (Reimers, 1992). It is clear from Table 5 that the
proportion of persons from Mexico who are naturalizing in any given year relative
to the total Mexican-born population has increased over time. During 1996 the
9
Table 5
Number of Naturalizations among Mexican-born Persons in the United
States: 1950–1996
Year
Number of
Naturalizations
Among Mexicans
Number per 10,000
Mexican-born Persons
In the United States
1995
1990
1980
1970
1960
67,238
17,564
9,341
6,195
5,913
110.9
40.9
4.2
0.8
1.0
Source: U.S. Immigration and Naturalization Service (1996).
number of immigrants becoming citizens increased substantially as those legalizing
their status under IRCA become eligible for naturalization, and as permanent resident
aliens seek to attain citizenship in order to be eligible for benefits as required by
legislation passed in the 104th Congress (U.S. Immigration and Naturalization
Service, 1997).
Growth in the Mexican-origin population in the United States is expected to
continue into the next century due to both natural increase and increased net immigration. According to Census Bureau population projections, the Hispanic-origin
population will add more people to the population in the next 60 years than all
other racial and ethnic groups combined (Day, 1995). Table 6 presents projections
of the size of the Hispanic-origin population based on U.S. Census projections.
These projections assume that the Hispanic population will receive the highest
number of immigrants than any other racial/ethnic group (350,000 annually). In
addition, the Census Bureau projections are based on the assumption that the higher
fertility rates of the Hispanic-origin population compared to other groups will persist. Fertility in the Hispanic-origin population is matched only by the Asian-origin
population in the United States.
The projections indicate that the Hispanic-origin population will make up
approximately 25 percent of the population by 2050 (Day, 1995). The last two
columns of Table 6 present the population projection for just the Mexican-origin
population based on its size relative to the Hispanic-origin population. Two
projections are presented based on slightly different assumptions. The first is based
on the assumption that the relative size of the Mexican-origin population as a segment
10
Table 6
Projected Size of the Mexican-origin Population
in the United States: 1995–2040
Projected Size (in Thousands) for the:
Mexican
Mexican
Population
Population
Year
Hispanic Population
(Estimate 1)1
(Estimate 2)2
1995
2000
2010
2020
2030
2040
26,936
31,366
41,139
52,652
65,570
80,164
16,135
18,788
24,642
31,539
39,276
48,018
16,337
19259
25,876
33,908
43,211
54,031
Source: Projection of the Hispanic Population from Day, Jennifer Cheeseman, Population Projections of the United States by Age, Sex, Race and Hispanic Origin: 1995
to 2050. U.S. Bureau of the Census, Current Population Reports, pp. 25-1130, U.S.
Government Printing Office, Washington, D.C., 1996.
Projection of the Mexican-origin population constructed by the authors.
1
Assuming that the proportion of the Hispanic population that is of Mexican origin
remains the same as observed in 1990 (59.9%).
2
Assuming the Mexican-origin population will continue to increase as a proportion
of the total Hispanic population by 1.5 percentage points per decade.
of the total Hispanic-origin population in the United States will stay the same. The
Mexican-origin population represented roughly 60 percent of the Hispanic-origin
population in 1990. Table 6 also presents a projection assuming that the Mexicanorigin population will continue to increase as a proportion of the Hispanic-origin
population over the next several decades. Based on these assumptions, the Mexicanorigin population in the United States will more than double in size over the next
sixty years. In fact, using these projections, the Mexican-origin population alone
will be larger than the projected size of the Black population by the year 2050.
The projections make it clear that the Mexican-origin population in the United
States will continue to increase for some time based on the characteristics of the
population as of 1990. In addition, there are other ways that the Mexican-origin
population can change in the near future without changes in fertility or mortality.
For example, as those who legalized under IRCA become eligible for citizenship
in the United States, they will also be eligible to petition to bring family members
11
to this country (Immigration and Naturalization Service, 1992). Mexican immigrants
have the largest pool of relatives who could become migrants to the United States
under the family reunification provisions than any other foreign-born group in the
United States (Schulte and Wolf, 1994; Woodrow and Peregay, 1991).
Another source of change that could affect the projected size of the Mexicanorigin population is changing rates of intermarriage and/or changing self identification among the children of mixed-ethnicity parents. The projections in Table 6
do not account for the possibility of changes in patterns of exogamy. Intermarriage
between racial/ethnic groups may alter the way future generations identify themselves given the present categories of race and ethnicity. Differential patterns of
exogamy may alter the projected size of these groups (Bean et al., 1997). Edmonston,
Lee and Passel (1994) have presented population projections adjusted for differential exogamy rates among Hispanics and other racial/ethnic groups. Increases in
exogamy are built into their projections (see Table 7) and show that the Hispanicorigin population in the United States could vary from between 50.9 million and
77.4 million people by 2040 depending on actual rates of exogamy. Table 7 also
presents the projected size of the Mexican-origin population based on the same
patterns of exogamy built into the Edmonston, Lee and Passel projections. These
projections demonstrate that, if the Mexican population remained approximately
Table 7
Projected Size of the Mexican-origin Population in the United States
Adjusted for Potential Exogamy: 1995–2040
1990
2000
2010
2020
2030
2040
Hispanic-origin Pop’n (in millions)
Mexican-origin Pop’n (in millions)
Single Ancestry
Only1
Single and
Mixed Ancestry2
Single Ancestry
Only3
Single and
Mixed Ancestry4
22.4
28.6
35.0
41.1
46.5
50.9
22.4
31.9
42.1
53.0
65.0
77.5
13.4
17.1
21.0
24.6
27.9
30.5
13.4
19.1
25.2
31.7
38.9
46.4
Source: Bean, Cushing, Haynes and Van Hook (1997), Edmonston, Lee and Passel (1994).
Notes: 1 Both parents are of Hispanic origin.
2
At least one parent is of Hispanic origin.
3
Both parents are of Mexican origin.
4
At least one parent is of Mexican origin.
12
60 percent of the total Hispanic-origin population, individuals of Mexican origin
would number between 30 and 46 million persons by the year 2040 depending
upon actual rates of exogamy.
Estimates of Authorized or Legal Mexican Immigration
Measuring Legal Immigration: Knowns
Administrative Statistics
Admissions for lawful permanent residence, legalization approvals, adjustments
to lawful permanent residence, and nonimmigrant arrivals are easily accessible
administrative statistics. These would be considered “knowns” in the sense that the
data sets are regarded as highly complete within the domain. Interpretive cautions
must be noted for using these administrative statistics for social science research.
First, those immigrants arriving as permanent residents may have had prior U.S.
residence experience or may anticipate short or long stays abroad. Survey responses
to questions about the timing of immigration may differ from recorded date of
lawful permanent residence. Second, generally-legalized immigrants are usually
presumed as having settled here for their lifetimes and at minimal risk of return
migration as a consequence of their sustained presence. Third, those adjusting to
lawful permanent residence from a nonimmigrant class may have substantial U.S.
residence histories, either continuous or on an intermittent basis. Fourth, arriving
nonimmigrants are presumed to be temporary residents, and the majority of nonimmigrant departures occur following short durations of saty.
Measuring Legal Immigration: Unknowns
The following sub-sections address the major uncertainties stemming from
“temporary” migration, emigration after legal immigration, incorporation of the
agriculturally-legalized population, and the ultimate immigration consequences of
the IRCA legalizations.
Presence of Nonimmigrants
A one-year entry cohort of nonimmigrant arrivals is comprised of (1) aliens
who depart and (2) aliens who stay or are lifetime migrants. Among those who
depart, most depart within a brief interval and others depart after stays of at least
one year. Among those who stay, some adjust to permanent resident status, and
others stay as unauthorized or undocumented, but either may have changed among
nonimmigrant classes. Those nonimmigrant arrivals followed quickly by departure
are not considered as counting toward population change and such individuals
13
would not meet residence rules for either census enumeration or inclusion in
national surveys. Those eventually departing after longer residence periods and
those ultimately becoming lawful permanent residents present accounting
difficulties. The critical questions is: As of a specific date, how many
nonimmigrants have stayed in the United States for at least one year or are likely
to do so? The magnitude of the accumulated number of present stayers across
various nonimmigrant arrival cohorts is needed to estimate the legally resident
foreign-born populations for dates falling within the transition between
nonimmigrant status and departure or adjustment to permanent status. Their
presence is hidden until their adjustments are recorded in immigrants statistics.
This problem is difficult conceptually, analytically, and empirically. The
appropriately detailed arrivals and departures statistics are not yet published for
monitoring the nonimmigrant population, although considerable improvements
have been made. Departures statistics have not been published regularly and are
incomplete because the departure portion of the I-94 form may not be collected
at exit or INS may receive it much later. Interpreting the net difference of 3.3
million for 1994 (22.1 million arrivals less 18.8 million departures [U.S.
Immigration and Naturalization Service 1996b]) is impossible without modeling
nonimmigrant processes of arrival, departure and adjustment over time with
modification for undercoverage.
The residence rules for the census stipulate that individuals shoulds be living
here on a permanent basis or should have lived here for at least six months. Therefore, even when migration may not be for the purpose of permanent residence, six
months of residence might be considered a threshold for considering nonimmigrants
as usual residents. The 1980 estimate of Warren and Passel included about 612,000
nonimmigrants whose class of admission was taken to imply “usual” residence—
243,000 refugees, 192,000 students, and 177,000 other aliens (Woodrow 1990).
Throughout the 1980s, the presumption was that newly-arriving nonimmigrants
becoming “usual” residents for several months were offset by departures, including adjustments of status of similarly “usually resident” nonimmigrants. This could
be a shaky assumption because the annual number of nonimmigrant arrivals has
tripled relative to 1970. A total of 1,150,000 nonimmigrants adjusted to lawful
permanent residence during 1990-1994. Thus there are about 230,000 annually
who are identified as long-term temporary migrants.
Emigration after Legal Immigration
The volume of authorized or legal immigration rose over the 1960s, 1970s and
1980s. Following the post-war period of low immigration and low emigration, the
magnitude of emigration after legal immigration, also known as return migration
14
or re-migration, also began to shift upward. Absent official counts for departing
immigrants, several indirect approaches described possible emigration levels for
the 1960s, 1970s, and 1980s decades (Warren and Peck, 1980: Warren and Kraly,
1985; Warren and Passel 1987; Woodrow-Lafield, 1996a; Ahmed and Robinson,
1994, Borjas and Bratsberg, 1996).
The crucial question is whether emigration levels for 1960-1980 are sufficiently
descriptive of emigration levels for 1960-1990 and 1960-1999, or whether
emigration has perpetually increased in the latter half of the 20th Century as the
foreign-born population increased dramatically. Emigration levels might be
unchanged because emigration rates may be lower among contemporary immigrant
residents than among earlier cohorts. Origin or other characteristics associated
with lower propensity to emigrate may be more highly represented among foreignborn residents. Indeed, the compositional mix of the foreign-born population has
shifted to include greater proportions of (1) Latin Americans and Asians for whom
emigration has seemed lower than for Europeans (Jasso and Rosenzweig, 1990);
Warren and Kraly, 1985) and (2) immigrants who entered under visa categories
associated with lesser likelihood of return migrating, such as refugees, asylees,
adjustees from nonimmigrant statuses, and formerly undocumented or temporarily
resident individuals.
The preponderance of evidence about emigration is more adequate for positing a broad range than for stating that emigration levels are higher in the 1980s
than in the 1970s. The empirical evidence is mixed. First, several studies support a
range for 1980 census coverage research of about 0.9 to 1.9 million foreign-born
emigrants. Second, there is variance among estimates of emigration for the 1980s.
A newly applied approach in the U.S. context, multiplicity sampling-based surveys of U.S. residents about nonresident relatives, supported a broad range for
emigration occurring over 1980-1989 (Woodrow-Lafield 1996a). In combination
with sensitivity analyses in Woodrow (1991b) based on using emigration rates by
age, sex, period of entry, and country or region of origin, the preliminary evaluation of 1990 census coverage employed an estimate of 1.33 million for net emigration of legally resident foreign-born for the 1980s and allowed for variation between 0.8 million and 2.2 million. A re-application of Warren and Peck’s (1980)
intercensal approach yielded a result toward the upper end of this range (Ahmed
and Robinson 1994). Although this study was taken to support higher emigration
in the 1980s than in the 1970s and a higher allowance for population programs, the
U.S. Bureau of the Census took an evenhanded approach in also increasing the
allowance for net population change due to net undocumented migration.
For the present purposes of positing estimates for net legal immigration as of
the 1980s and 1990s, we make assumptions about the level and composition of
emigration flows that are generally consistent with prior research for the 1960s
15
and 1970s. For post-1989 analyses, alternative series will show the effects of varying
assumed emigration from 95,000 to 195,000 annually. Legal foreign-born emigrants
will be distributed to Mexico as country of origin and to all other countries of
origin on the same basis as for undocumented research (Woodrow and Passel 1990;
Woodrow 1992c).
The Mexico-born population has increased dramatically since 1950, but that
increase has been dominated recently by legal immigration—primarily family-based
and legalization-based. In one sense, there might seem to be lesser propensity for
return migration given a greater density on legal status, greater demographic diversity, and possibly greater representation of sending communities at migration
maturity. Alternatively, the Mexico-born population could ultimately reach a time
at which Mexican return migration could emerge as more easily discernible, despite limitations of methodologies, simply because of its volume as a function of
the larger size of immigrant cohorts over the 1970s, 1980s, and 1990s. Such a shift
could be detectable, if not precisely measurable, by comparing multiplicity sampling-based estimates of Mexican emigrants over time, as Woodrow-Lafield (1996a)
found for the post-IRCA period between 1987 and 1988.
The SAWs Population
In referring to the agricultural legalization, meaningful distinctions exist among
SAW applicants, SAW-approved beneficiaries, SAW-default beneficiaries, and residents becoming SAW-approved beneficiaries. The SAW beneficiaries may not be
presumed automatically as living in the United States because their “proof” of
agricultural work experience was insufficient for establishing usual residence in
the United States. Migrant agricultural workers have historically commuted for
lengthy periods of time as part of the settlement process (Massey 1986; Lowell
1992; Tilly 1990). Because about 700,000 SAW applications were filed in May
1988-November 1988 (498,000 in the last two months), the SAW program may
have been a magnet for aliens seeking U.S. residence status and may have ultimately promoted migration to and settlement in the United States (Also, see Martin 1990, 1994, 1996.)
Further confusing the issue of whether SAW beneficiaries live in the United
States or their origin country, which was Mexico for 81.6 percent, the INS
automatically granted lawful permanent resident status to all SAW beneficiaries.
That benefit was extended to both SAW-approved beneficiaries and SAW-default
beneficiaries, whose applications INS simply failed to deny, with about 900,000
becoming “lawful permanent residents” by the default deadline of December 1,
1990. Thus, the single action of SAW application yielded entitlement for U.S.
permanent residence.
16
Figure 3. Legally Resident Foreign-born in 1989
by Mexican-born and Resident SAWs
There are limited insights to SAWs’ behavior following legalization. The
National Agricultural Workers Survey (NAWS) acquired individual migrant workers’
legal status; almost one-half of the migrant workforce in 1989—1991 has legalized
under IRCA (Gabbard, Mines, and Boccalandro 1994). Samardick (1995) reported
that about 32 percent of Mexico-born migrant workers in 1993-1994 had received
SAW status and that about 7 percent had generally legalized after long-term
undocumented residence. Many of the SAW beneficiaries appear to have continued
working in seasonal agricultural services.
Another indicator of SAW beneficiaries’ residence in the U.S. rather than their
origin country will be their behavior in seeking to naturalize. Naturalization statistics for fiscal year 1996 showed a continued upward trend, but application levels
for naturalization among eligible generally-legalized immigrants or SAW beneficiaries are not known. Application rates among the generally-legalized population
have been tracked in only a very limited fashion (U.S. Department of Labor
(1996:107).
Immigrant Flow Effects from IRCA
The presence of IRCA beneficiaries’ family members in the United States must
be viewed carefully in building an accounting model for the legally resident foreignborn population. The demographic consequences of the general legalization program
under IRCA will be considerable with as many as 2.5 million future immigrants
17
related to these legalization beneficiaries, including 1.6 million Mexican relatives
(Woodrow-Lafield 1994a). Approximately 136,000 spouses, 223,000 children,
30,000 parents, 130,000 siblings, and 102,000 other relatives are estimated as living
in the IRCA beneficiary households and having non-resident statuses (family
fairness, temporary visa, other, or missing). Within households of legalized Mexican
immigrants, there were 91,000 spouses, 159,000 children, 19,000 parents, 99,000
siblings, and 69,000 other relatives in nonpermanent statuses, totaling 436,000
(unpublished analyses by Woodrow-Lafield). In a demographic accounting analysis
of the resident population, resident dependents of IRCA beneficiaries will be
incorporated in the estimated legally resident foreign-born population in a lagged
fashion as they become legal immigrants with the allocated visas for 1992-1994,
with second preference (or first, third, or fourth preference) visas in some year, or
under provisions for immediate relatives (parents, spouses, or minor children) of
U.S. citizens.
IA90 specified that up to 55,000 visas might be granted for spouses and
children of legalization beneficiaries to avoid family disruption. This largesse
was apparently insufficient because (1) a lesser amount resulted—140,000; (2)
the second preference visa waiting list counts associated with legalization
beneficiaries were 739,774; 853,382; and 824,000 in fiscal years 1993, 1994 and
1995 (U.S. Department of State 1993, 1994, 1995 U.S. Commission on Immigration
Reform 1995). Many (one half million) of these spouses and children are probably
related to beneficiaries of the SAW or agricultural legalization (Woodrow-Lafield
1995b). The waiting list under second preference is so clogged that waiting times
for new applicants are growing progressively longer.
A more expedient way for these close family members to legally immigrate
to the United States will be the two-tier processes of the IRCA beneficiary’s
naturalization and sponsorship of their spouses and minor children under immediate
relatives provisions for which there are no limitations except for those who were
minor children at the time of visa petition filing who aged into adulthood and
were ineligible for visa issuance. Among Mexican respondents in the 1992 LPS,
nearly three-quarters indicated they would either “definitely” or “probably” apply
for naturalization upon becoming eligible (Woodrow-Lafield 1995c). This study
supported a cost-benefits strategy in naturalization decision-making in that having
a co-resident sibling without permanent status and having a parent or sibling
intending to immigrate are significantly associated with intending to apply for
naturalization. The numbers of spouses and children who could become legal
immigrants under immediate relatives’ provisions during 1996-1999 could exceed
one half million.
18
Demographic Accounting for Unauthorized
or Legal Migration
Legally Resident Foreign-born Population in 1980
Warren and Passel (1983, 1987a, b) first formulated a baseline estimate for the
alien component using the Annual Alien Address Registration Program for January
1980 according to self-reported residence status. The 1980 alien data were adjusted
for estimated underregistration of 11.1 percent, resulting in an overall increase of
12.5 percent. For Mexico, Warren and Passel estimated that 7.3 percent of legally
resident aliens had failed to register (Passel 1991). An estimate of naturalized citizens
in the 1980 census was based on both census reporting as naturalized citizens and
a demographic estimate constructed by surviving naturalizing immigrants over time,
as identified with INS administrative naturalizations statistics. A major criticism
directed at this work on the undocumented population was that the authors assumed
that INS sources correctly recorded naturalizations over 1960-1980 (Hill 1985b),
but classification by citizenship was unnecessary for derivation of an undocumented
estimate, and subsequent demographic accounting was for the foreign-born category.
The Warren-Passel estimate for 1980 of 12,084,000 legally resident foreignborn persons, including 7,816,000 aliens and 6,118,000 naturalized citizens was
meant to represent the complete population of legally resident foreign-born persons as of January 1980. Included were 2,326,000 persons of Mexican birth, with
2,121,000 aliens and 205,000 naturalized citizens. An obvious weakness is an inconsistency with 1980 census data for foreign-born persons entered before 1960 in
that the census counts were lower than Warren and Passel’s estimate for all countries or regions other than Mexico. Demographic research on legal status of the
foreign-born population has emphasized the “Entered After 1960” population, with
inclusion of Mexicans who entered pre-1960.
The nature of the data collection over a one-month period also raises concerns
because the population estimate would probably over-represent shorter durations
and lead to over-estimating the population entered for the most recent time period.
Hill (1985b) raised questions about over-reporting for Mexico, among other countries, possibly as a result of misreporting by temporary residents in the category for
permanent resident. Subsequently, Passel (1991) allowed for greater variability in
the legally resident alien component for the Mexican population (+10 percent)
than for the non-Mexican population (+3 percent), noting that undocumented migrants might have erroneously registered.
The estimate of legally resident foreign-born persons as of 1980 by Warren
and Passel can be considered a “standard” in several senses, and it became a
foundation for using a components-of-change method to derive post-1980 estimates
for legally resident foreign-born populations in the United States. The major
19
components of change are estimated mortality, assumed emigration, admissions of
lawful permanent residents and certain groups of arriving refugees, and other
transitions to lawful permanent residence by persons already living in the United
States (including adjustments and legalizations). This methodology was designed
for consistency with the Census Bureau’s methodologies for demographic analysis
and postcensal population estimates.
An accounting for components of change for the resident population was equivalent to accounting for components of change in the legally resident population
before 1980 because an undocumented presence had not yet been measuraæble.
After the 1980 census apportionment counts exceeded the independent estimate,
the Census Bureau endeavored to improve estimates of the number of illegal aliens
and make public a sufficient number of undercount estimates to illustrate the uncertainties in the methods (ASA Technical Panel, 1984). To this end, a systematic
research program at the Census Bureau monitored net legal immigration in the
1980s and indirectly monitored net undocumented migration by partitioning survey estimates for the foreign-born population into legal and undocumented components (Passel and Woodrow 1987; Woodrow, Passel and Warren 1987; Woodrow
and Passel, 1990; Woodrow 1992c).
Table 8 summarizes the 1970-1990 time series of estimates of the foreignborn population, legally resident foreign-born estimates, and estimates of unauthorized residents in surveys or censuses. Post-1986 estimates required accounting
for IRCA-legalized aliens’ transitions from undocumented resident to legal resident. Those legalizing on the basis of having lived here continuously in an undocumented status since before 1982 are prima facie permanent residents. The figures
in Table 8 incorporate most of the general legalizations, but alternative estimates
based on allowing for agricultural legalizations are discussed below.
To the degree that there is undercoverage of either the legally resident or undocumented residents, there will be underestimation of the unauthorized component (Woodrow-Lafield 1995a). Because foreign-born undercoverage is not known,
a potpourri of rationales have been discussed for a range on the total number of
unauthorized residents over 1980-1990. Despite the passage of time, these ranges
are not really very different. The most consensual is the range for 1980 that relies
on several studies suggesting that the probable upper bound of the unauthorized
population was 3.5 to 4 million (Bean, King, and Passel 1983; Levine, Hill, and
Warren 1985; Passel and Robinson 1988; Heer and Passel 1987.
These studies were the foundation for the net unauthorized migration component
for evaluating the 1990 census (Woodrow 1991a) which is discussed more later. It
must be noted that an estimate for legally resident foreign-born population was
implicit rather than explicitly stated and that the net “unauthorized” migration
component possibly included agriculturally legalized residents. The last two studies
20
21
7.0% 14,379,000
7.3% 15,154,000
7.5% 15,754,000
8.0% 16,628,000
8.0% none given
14,139,000
13,633,000
16,237,000
17,185,000
17,785,000
19,090,000
19,768,000
19,724,000
April 1983 (14+)
June 1986
June 1988
Nov. 1989
Projected
April 1990
1990 Census
1990 Census
9,230,000
17,690,000
17,749,000
15,279,000
15,735,000
16,690,000
11,540,000
13,079,000
12,082,000
9,739,723
11,474,000
All periods
14,354,000
none given
12,473,000
13,104,000
13,354,000
7,855,000
9,911,000
7,173,000
3,316,928
7,036,000
Post-1960
Legally resident
foreign-born in U.S.
2,274,000
1,975,000
1,906,000
2,050,000
2,400,000
2,093,000
3,158,000
2,057,000
0
1,724,000
Estimated
unauthorized
residents
in survey
or census
none given
1.7 to 3.1
3.3
1.9 to 4.5
2.3 to 5.0
none given
2.0 to 5.0;
1.5 to 3.5;
2.0 to 4.0
none given
3.0 to 5.0
2.5 to 3.5;
0.8
none given
Hypothetical
total number
or range
(in millions)
Woodrow-Lafield (1995)
Clark et al. (1994)
Passel & Robinson (1988)
Passel & Woodrow (1987)
Woodrow, Passel, & Warren (1987)
Warren & Passel (1983, 1987)
Passel (1985b)
Passel & Robinson (1988)
Fay, Passel, & Robinson (1988)
Hill (1985)
Levine, Hill, & Warren (1985)
Passel & Woodrow (1987)
Woodrow, Passel, & Warren (1987)
Passel & Woodrow (1986)
Woodrow & Passel (1990)
Woodrow (1990, 1991b, 1992b)
Woodrow (1991b)
Relevant Sources
Source: Woodrow-Lafield, Forthcoming
Note: Most foreign-born population figures include estimated amounts for misreporting as native foreign-born persons.
7.4% 9,949,000
6.8% 13,069,000
6.2%
3,316,928
8,760,000
1980 Census
4.0%
5.8%
9,739,723
13,198,000
Post-1960
1970 Census
Nov. 1979
%
All Periods
Date of
Estimate
Foreign-born in census or survey
Table 8
Estimates for Foreign-born, Legally Resident, and Unauthorized Populations
Based on Demographic Accounting: 1970-1990
mentioned in table 8 (Woodrow-Lafield 1995a; Clark et al., 1994) make allowances
for nonspecific sources of legal immigration, including agriculturally legalized
residents, and we return to these results a closer examination of studies for the
1979-1989 period.
The legally resident Mexico-born population in the United States increased
from about 1.4 million in 1980 to 3.0 to 3.5 million for 1990 (Table 9), depending
on particular assumptions. The unauthorized population of Mexican birth appears
to have fluctuated and to have declined slightly for 1990 relative to 1980, but this
appearance may be artifactual due to the survey or census estimate. Prior to IRCA,
extrapolation of studies of average population change due to net unauthorized
migration from Mexico implied there were as many as 2.5 to 3.5 million unauthorized
Mexican residents, but the post-IRCA range was lower—1.0 to 2.2 million (Woodrow
-Lafild 1996e). These estimates for legally resident foreign-born populations are
only as accurate as they are unbiased from data gaps on emigration or return
migration and unknown long-term immigration associated with nonimmigrants or
agriculturally legalized persons. Exercising expert judgment is inescapable, but
guiding strategies are nonexistent. The number of unauthorized residents in 1990
was certainly below six million (Woodrow-Lafield, 1997).
Without Accounting for IRCA Legalizations
Prior studies showed post-1986 estimates for the legally resident foreign-born
population without any amnestied aliens pursuant to IRCA only for the purpose of
estimating net population change due to undocumented immigration. Without allowing for legalization pursuant to the amnesty provisions of IRCA, the foreignborn population legally resident would have grown from 7,036,000 to 11,440,000
over 1979-1989 (second tier, Table 9). This increase is only from post-1981 immigration. Recently admitted legal Mexico-born immigrants accounted for slightly
more than one-tenth of net legal immigration for the post-1981 entry period.
With Accounting for Generally
Legalized Immigrants
The featured or preferred estimates for the legally resident foreign-born
population showed an increasing trend over 1979-1989. The rate of increase was
greater for the Mexico-born population legally resident as the number more than
doubled over that decade from 1,388,000 to 2,522,000. Without considering origin,
most of the increase is attributable to post-1981 immigration. With closer
examination, most of the increase for the Mexico-born population falls within
the pre-1981 entry reference period—almost wholly from the IRCA legalization
22
Table 9
Estimates of Net Legal Immigration with Legalizations,
1979–1989, Total and Mexican-born
Total (in thousands)
Data and Source
Mexico-born (in thousands)
Total
Entered
Before
1982
Entered
After
1981
Entered Entered
Before
After
1982
1981
Total
7,036
7,173
9,911
12,473
13,104
7,036
7,173
7,595
9,114
8,887
–
–
2,316
3,359
4,217
1,388
1,400
1,657
2,985
2,999
1,388
1,400
1,397
2,597
2,522
–
–
260
389
477
7,036
7,173
9,911
10,728
11,440
7,036
7,173
7,595
7,369
7,223
–
–
2,316
3,359
4,217
1,388
1,400
1,657
1,766
1,837
1,388
1,400
1,397
1,378
1,360
–
–
260
389
477
7,036
7,173
9,911
12,473
13,354
7,036
7,173
7,595
9,114
8,887
–
–
2,316
3,359
4,467
1,388
1,400
1,657
2,985
3,211
1,388
1,400
1,397
2,597
2,522
–
–
260
389
689
7,036
7,173
9,911
12,473
13,604
7,036
7,173
7,595
9,114
8,887
–
–
2,316
3,359
4,717
1,388
1,400
1,657
2,985
3,449
1,388
1,400
1,397
2,597
2,522
–
–
260
389
927
7,036
7,173
9,911
12,473
13,879
7,036
7,173
7,595
9,114
9,662
–
2,316
3,359
4,217
4,992
1,388
1,400
1,657
2,985
3,774
1,388
–
1,400
260
1,397
389
2,597
477
3,297 1,252
Preferred
1979, Passel and Woodrow (1987)
1980, Passel and Woodrow (1984)
1986, Woodrow, Passel and Warren (1987)
1988, Woodrow and Passel (1990)
1989, Woodrow (1991a, 1992c)
Without any IRCA legalizations
1979, Passel and Woodrow (1987)
1980, Passel and Woodrow (1984)
1986, Woodrow, Passel and Warren (1987)
1988, Woodrow and Passel (1990)
1989, Woodrow (1991a, 1992c)
With general legalizations and low
number of SAW beneficiaries as residents
1979, Passel and Woodrow (1987)
1980, Passel and Woodrow (1984)
1986, Woodrow, Passel and Warren (1987)
1988, Woodrow and Passel (1990)
1989, Woodrow (1991a, 1992c)
With general legalizations and moderate
number of SAW beneficiaries as residents
1979, Passel and Woodrow (1987)
1980, Passel and Woodrow (1984)
1986, Woodrow, Passel and Warren (1987)
1988, Woodrow and Passel (1990)
1989, Woodrow (1991a, 1992c)
With general legalizations and high number
of SAW beneficiaries as residents
1979, Passel and Woodrow (1987)
1980, Passel and Woodrow (1984)
1986, Woodrow, Passel and Warrent (1987)
1988, Woodrow and Passel (1990)
1989, Woodrow (1991a, 1992c)
23
Table 9 (Continued)
Total (in thousands)
Data and Source
Mexico-born (in thousands)
Total
Entered
Before
1982
Entered
After
1981
Total
Entered Entered
Before
After
1982
1981
7,036
7,173
9,911
12,473
14,104
7,036
7,173
7,595
9,114
8,887
–
–
2,316
3,359
5,217
1,388
1,400
1,657
2,985
3,799
1,388
–
1,400
–
1,397
260
2,597
389
2,522 1,277
With general legalizations and nearly all
SAW beneficiaries as residents
1979, Passel and Woodrow (1987)
1980, Passel and Woodrow (1984)
1986, Woodrow, Passel and Warren (1987)
1988, Woodrow and Passel (1990)
1989, Woodrow (1991a, 1992c)
of aliens proving continuous undocumented residence since before January 1,
1982. As a reminder, these estimates of the legally resident foreign-born population
were produced under the auspices of the Census Bureau’s 1980 and 1990 census
coverage evaluation programs and, accordingly, are intended to represent those
individuals meeting the Census Bureau’s criteria for living in the United States
on a usual basis.
With Incorporation of Agriculturally Legalized
Beneficiaries as Residents
Recalling earlier discussions about the SAW legalization program, the issue of
SAW applicants’ inclusion in the legally resident estimate, national surveys or the
census, and in survey-based undocumented estimates were not very important during 1988-1990. For example, the review of the unauthorized immigration component by Himes and Clogg (1992) mentioned only the generally legalized immigrants. Until the deadline of December 1, 1990, the INS might have refused many
of the applicants on the basis of having shown insufficient grounds. Making any
allowance for agricultural legalization beneficiaries’ residence affects primarily
the overall foreign-born and Mexico-born legally resident populations.
Shown in the lower four tiers of Table 9 are illustrative estimates based on
alternative assumptions about inclusion of SAW applicants as legally resident for
November 1989. The scenarios, similar to those presented in Woodrow and Passel
(1990) and Woodrow (1992c), are:
• Low assumption of SAW beneficiaries as residents, for which each SAW
beneficiary is assumed to have resided in the United States, on average,
for three months, implying that 250,000 would be included;
24
• Moderate assumption of SAW beneficiaries as residents, for which each
SAW beneficiary is assumed to have resided in the United States, on
average, for six months, implying that 500,000 would be included;
• High assumption of SAW beneficiaries as residents, for which 550,000
SAW beneficiaries (including 100,000 Group I and 450,000 Group II)
are assumed as continuously resident in the United States and for which
450,000 SAW beneficiaries are assumed to have resided in the United
States, on average, for six months, implying that a total of 775,000 would
be included;
• “All” assumption of SAW beneficiaries as residents, for which nearly
all SAW beneficiaries are assumed to have resided in the United States
permanently, for inclusion of 1,000,000.
The effect of incorporating SAW beneficiaries as residents increases the post1981 portion of net legal immigration with especially marked increase for the
Mexico-born population. In light of the heavily male composition of the SAW
applicant pool, the 1988 and 1989 studies also considered composition by sex.
Given implications of these legally resident estimates for derivation of undocumented estimates, it appeared in the late 1980s as if the demographic and origin
characteristics of the SAW applicant pool constrained the feasible assumptions to
the “low” and “moderate” ones. Allowing for inclusion of more than 500,000 SAW
applicants (perhaps 425,000 from Mexico) in the legally resident estimate led to
unbalanced sex ratios and implausible undocumented estimates based on the 1988
and 1989 CPS (Woodrow and Passel 1990; Woodrow 1991a, 1992c). Some or many
SAWs may certainly have been living in the United States prior to final INS processing and simply have been omitted from the CPS estimates of the foreign-born
population. The likelihood of high census and CPS undercoverage for SAW beneficiary residents is obvious, particularly if they resemble agricultural migrant
workers (Kissam 1993; La Cooperativa Campesina de California 1991). Gabbard,
Kissam, and Martin (1993) discussed the travel patterns of migrant workers as
explanations for their finding of extremely high census undercoverage for this special population.
Demographic analysis of 1990 census coverage required an estimate of the
total resident population, including the undocumented population residing in the
United States on April 1, 1990 by May 1991, prior to the Secretary of Commerce’s
decision on whether to adjust the 1990 census apportionment counts for
undercoverage. However, demographers could not replicate previous analyses, that
is, compare the legally resident foreign-born population estimate as of Census Day
1990 with the 1990 census count of the foreign-born population which was unknown
until early February of 1992 (U.S. Bureau of the Census 1993a. b). For the
25
demographic analysis program over 1990-1991, the major emphasis was on
measuring overall undercoverage of all residents by age, sex, and race with lessor
emphasis on legally resident undocumented populations differentiation. In Robinson
et al’s (1993) analysis of 1990 census coverage, the implicit estimate for legal
foreign-born residents as of Census Day 1990 would be 16.7 million as a minimum
after incrementing the November 1989 estimate of Woodrow (1991a, 1992c) with
250,000 additional legal immigrants over December 1989-March 1990 as described
in Woodrow (1992b) and Woodrow-Lafield (1995a). That figure would have included
at least 3 million Mexico-born legal residents. For the “entered since 1960”
population, the overall figure would be 13.4 million.
A prime source of uncertainty about the legally resident foreign-born population
for 1990 is the size of the resident population having benefited from the agricultural
legalization provisions of IRCA. With assumptions about resident SAW beneficiaries,
the overall estimate could increase to 17.6 million and the Mexico estimate would
increase markedly to 3.8 million. The component for legal immigration over the
1980s was bounded by 5.9 and 8.3 million for modeling uncertainty in the total
resident estimate (Robinson et al., 1991, 1993). The two published estimates for
legally resident foreign-born persons 1990 shown in Table 8 and for the Mexicoborn portion shown in Table 9 are similar in their methodological divergence from
pre-1990 census studies. Citing nonspecific sources of legal immigration, including
SAW beneficiaries, nonimmigrants becoming permanent residents in the 1990s,
special EVD and TPF statuses, and dependents of IRCA-legalized beneficiaries,
Woodrow-Lafield (1995a) used estimates of 14.354 million and 17.690 million for
the legally resident foreign-born population entered since 1960 and entered in all
time periods. Clark et al. (1994) similarly allowed explicit amounts for SAW
beneficiaries’ presence, foreign students, and other nonimmigrants for estimates of
17.749 million, including 3.469 million Mexicans.
Most of the lawful permanent resident admissions in Fiscal Years 1990 and
1991 were legalization adjustments. In 1990, most of these legalization adjustments
were to generally legalized immigrants, and 1991 was the peak year for agricultural
legalization adjustments, primarily of the SAW-default approved beneficiaries.
Net Legal Immigration Alternative Series,
Varying Emigrants, SAW Beneficiaries as
Residents, or Other Nonspecific
Alternative series of estimates for net legal immigration as of 1990 and for
1995 are presented in Table 10 that consider uncertainties as to emigration of legal
immigrants, incorporation of SAW beneficiaries as U.S. resident, and nonspecific
sources of net legal immigration. The range for the low (95,000), moderate (133,000),
26
27
14,004
13,641
13,092
14,304
13,941
13,392
14,554
14,191
13,642
With low-zero allowance for nonspecific,
Without any allowance for SAW beneficiaries as residents,
1. With low assumption for emigration (95,000)
2. With moderate assumption for emigration (133,000)
3. With extreme assumption for emigration (195,000)
With low-zero allowance for nonspecific,
With low allowance for SAW beneficiaries as residents
(300,000, 250,000 Mexican),
4. With low assumption for emigration (95,000)
5. With moderate assumption for emigration (133,000)
6. With extreme assumption for emigration (195,000)
With low-zero allowance for nonspecific,
With moderate allowance for SAW beneficiaries as residents
(550,000, 450,000 Mexican),
7. With low assumption for emigration (95,000)
8. With moderate assumption for emigration (133,000)
9. With extreme assumption for emigration (195,000)
Description and Assumptions
Total
Entered
1960-1990
3,757
3,714
3,649
3,557
3,514
3,449
3,307
3,264
3,199
Mexico-born
Entered
Before 1990
17,375
16,831
16,007
17,125
16,581
15,757
16,825
16,281
15,457
Total
Entered
1960-1995
Table 10
Net Legal Immigration, 1990 and 1995, Alternative Series, Varying Assumptions on Specificity,
Residence of Agricultural Legalization Beneficiaries, and Emigration
4,378
4,314
4,216
4,178
4,114
4,016
3,928
3,864
3,766
Mexico-born
Entered
Before 1995
28
14,854
14,491
13,942
15,004
14,641
14,092
15,254
14,891
14,342
15,554
15,191
14,642
With low-zero allowance for nonspecific,
With extreme allowance for SAW beneficiaries as residents
(850,000, 700,000 Mexican),
10. With low assumption for emigration (95,000)
11. With moderate assumption for emigration (133,000)
12. With extreme assumption for emigration (195,000)
With moderate allowance for nonspecific (700,000, 250,000 Mexican),
With low assumption of SAW beneficiaries as residents
(300,000, 2500,000 Mexican),
13. With low assumption for emigration (95,000)
14. With moderate assumption for emigration (133,000)
15. With extreme assumption for emigration (195,000)
With moderate allowance for nonspecific (700,000, 250,000 Mexican),
With moderate allowance for SAW beneficiaries as residents
(550,000, 450,000 Mexican),
16. With low assumption for emigration (95,000)
17. With moderate assumption for emigration (133,000)
18. With extreme assumption for emigration (195,000)
With moderate allowance for nonspecific (700,000, 250,000 Mexican),
With extreme allowance for SAW beneficiaries as residents
(850,000, 700,000 Mexican),
19. With low assumption for emigration (95,000)
20. With moderate assumption for emigration (133,000)
21. With extreme assumption for emigration (195,000)
Description and Assumptions
Total
Entered
1960-1990
Table 10 (Continued)
4,257
4,214
4,149
4,007
3,964
3,899
3,807
3,764
3,699
4,007
3,964
3,899
Mexico-born
Entered
Before 1990
18,375
17,831
17,007
18,075
17,531
16,707
17,825
17,281
16,457
17,675
17,131
16,307
Total
Entered
1960-1995
4,878
4,814
4,716
4,628
4,564
4,466
4,428
4,364
4,266
4,628
4,564
4,466
Mexico-born
Entered
Before 1995
29
15,854
15,491
14,942
With extreme allowance for nonspecific (1,000,000, 800,000 Mexican),
With extreme allowance for SAW beneficiaries as residents
(850,000, 700,000 Mexican),
28. With low assumption for emigration (95,000)
29. With moderate assumption for emigration (133,000)
3.0. With extreme assumption for emigration (195,000)
Note: See text for explanation of various assumptions and other details of these calculations.
Sources: Woodrow (1991a, 1992c); Woodrow-Lafield (1995, 1996).
4,557
4,514
4,449
15,554
15,191
14,642
With extreme allowance for nonspecific (1,000,000, 800,000 Mexican),
With moderate allowance for SAW beneficiaries as residents
(550,000, 450,000 Mexican),
25. With low assumption for emigration (95,000)
26. With moderate assumption for emigration (133,000)
27. With extreme assumption for emigration (195,000)
4,807
4,764
4,699
4,357
4,314
4,249
Mexico-born
Entered
Before 1990
With extreme allowance for nonspecific (1,000,000, 800,000 Mexican),
With low assumption of SAW beneficiaries as residents (300,000, 250,000 Mexican)
22. With low assumption for emigration (95,000)
15,304
23. With moderate assumption for emigration (133,000)
14,941
24. With extreme assumption for emigration (195,000)
14,392
Description and Assumptions
Total
Entered
1960-1990
Table 10 (Continued)
18,675
18,131
17,307
18,375
17,831
17,007
18,125
17,581
16,757
Total
Entered
1960-1995
5,428
5,364
5,266
5,178
5,114
5,016
4,978
4,914
4,816
Mexico-born
Entered
Before 1995
and extreme (195,000) assumptions about annual levels of emigration is narrow,
although those differences would accumulate over the number of years. For the
Mexico-born, these assumed amounts of emigration are slight—9,000, 13,000, or
20,000 in accordance with Warren and Passel (1987b). The range for incorporation
of SAW beneficiaries as residents is 300,000 (250,000 for Mexico), 550,000 (400,000
for Mexico), or 850,000 (700,000 for Mexico). The range for nonspecific sources
of legal immigration is zero for the low, 700,000 (250,000 for Mexico), or 1,000,000
(800,000 for Mexico). This latter set of assumptions is intended to encompass those
individuals whose status might be considered as neither legal nor undocumented at
the present time who would become legally resident especially as possible through
naturalization of a relative who is an IRCA legalization beneficiary.
The columns for net legal immigration for entry 1960-1990 are based on carrying forward the estimated legally resident foreign-born population of Woodrow
(1991a, 1992c) from December 1, 1989 to April 1, 1990 primarily with additional
legal admissions and additional general legalizations for most tiers. The columns
for net legal immigration for 1960-1995 are constructed by surviving the 1989
base estimate until 1995, adding surviving numbers of admissions of lawful permanent residents 1990-1995 (net of legalization adjustments), subtracting estimated
emigrants, and adding generally legalized, agriculturally legalized, and nonspecific components as indicated.
The first tier of estimates (1) through (3) for the legally resident foreign-born
population or net legal immigration as of 1990 or 1995 are most consistent with the
Census Bureau’s procedures for counting individuals as contributing to the resident
population as immigrants or settlers. This set is the lowest representation of net legal
immigration. The second tier of estimates (4) through (6) is slightly higher to reflect
a low allowance for agriculturally legalized residents. With set (5), the estimate is
about the same as that of Clark et al. (1994). Among all the estimates, including the
other tiers, sets (7) through (30), the amount of net legal immigration as of 1990
ranged between 13,092,000 (3) and 15,854,000 (28). The amount of net legal immigration from Mexico as of 1990 ranged between 3,199,000 (3) and 4,807,000 (28).
Figure 4 depicts net legal immigration for 1979-1995 with sets (2) and (17) for all
countries and for Mexico. Depending upon which alternative series might be the most
accurate, the divergence from prior estimation strategies would be greater or lesser.
Net legal immigration from all countries over 1960-1995 shows an increase of
more than 2 million. The low estimate appears in set (3)—15,457,000—and the
high estimate in set (28) is 18,675,000. Net legal immigration of Mexicans as of
1995 ranged from 3,766,000 (3) to 5,428,000 (28). The extreme allowance for
nonspecific sources of legal immigration may be beyond the range of reality, so
that these upper limits might be shifted downward to set (19)- 18,375,000 for all
countries and 4,878,000 for Mexico.
30
Figure 4. Net Legal Immigration, 1979-1995, Alternative Series
To summarize, the upward trend in legal immigration to the United States and,
for Mexico, the focused impact of IRCA’s amnesty programs, account for a gradually increasing presence of legally resident immigrants since 1980. The precise
magnitude is difficult to pinpoint because the extent of U.S. residence among agriculturally legalized individuals, the volume of transitions from undocumented status into lawful permanent residence among family members of legalized immigrants, and timely accounting of nonimmigrants in the United States are not known.
Ways of improving estimation for legally resident foreign-born populations are
straightforward in concept, but few of the statistical improvements recommended
in Levine, Hill, and Warren (1985) or others recommended have been accomplished.
The quantity of legal migration is more conservatively estimated with traditional
definitions of permanent migration than with less restricted, but probably truer,
inferences from multiple data sources.
Estimates of Undocumented Migration
The purpose of this section is to provide an overview of the best analytical
approaches and estimates of the stock and flow of the unauthorized Mexican migrant population from the late 1970s to the present. In describing the prevailing
methods used for estimating the unauthorized migrant population, including the
unauthorized Mexican migrant population, during the late 1970s, 1980s, and 1990s,
we illustrate how the methodology and data used for making estimates of the stock
and flow of the unauthorized migrant population in the United States in general
and the unauthorized Mexican migrant population in particular have changed over
the past two decades. We highlight how these changes have led to improvements
and, in some cases, to increased inaccuracy associated with estimates of particular
components of the unauthorized population. We do not review every individual
31
estimate of the unauthorized Mexican migrant population because many studies
have already been summarized and evaluated competently in other reviews (Keely,
1977; Briggs, 1984; Corona, 1982; Siegel, et al., 1980; Tuirán, 1984, 1994; Hill,
1985b; Bean, King, and Passel, 1986; Bean, Telles, and Lowell, 1987; Edmonston,
Passel, and Bean, 1990; Passel, Bean, and Edmonston, 1990; Durand and Massey,
1992; GAO, 1993; Clark, et al., 1994). Rather, we summarize and assess the conclusions of these reviews and describe individual studies where appropriate.
Concepts and Definitions
An unauthorized migrant is a person who resides in the United States but is
not a U.S. citizen or permanent resident alien or authorized visitor. Various terms
have been used to describe such persons, including undocumented immigrant,
undocumented alien, undocumented migrant, unauthorized immigrant, and
unauthorized migrant, each of which has a slightly different meaning and
connotation. As noted above, we use the term “unauthorized migrant” because it
best applies to the population whose size and growth we here attempt to estimate.
Not all unauthorized migrants are undocumented; some arrive in the U.S. with
legal documents but later either stay beyond the expiration date of their visa or
otherwise fail to comply with the terms of their entry (such as persons who legally
cross the border with border crossing cards but do so to work, which violates the
terms of the card). Also, not all unauthorized migrants are immigrants; many are
temporary migrants who intend to and do in fact return to their countries of origin
within reasonably short periods of time.
The types of data available and the methodology used to obtain estimates of
the unauthorized migrant population sometimes depend on the route through which
unauthorized status was attained. There are several ways to become an unauthorized
migrant. These include entering without inspection, using fraudulent documentation,
or violating the terms of border crossing cards. All violators of these types end up
in a category the Immigration and Naturalization Service (INS) calls entrants without
inspection (EWIs). Another way involves entering legally as a nonimmigrant but
subsequently violating the terms of the entrance visa or other terms of entry (usually
through failing to leave the U.S. by the time the visa expires). These are often
called “visa overstayers.” Still another way involves entering as a legal resident
alien but subsequently violating the terms of entry (e.g., through committing a
criminal act or using a fraudulent marriage as a basis for entry). Most studies that
attempt to estimate unauthorized migrants separately by type of entry focus on the
two largest of these groups, EWIs and visa overstayers.
The data and methodology used to estimate the unauthorized Mexican migrant
population also depend on whether the estimate refers to the stock of the population
32
or the flow of the migratory stream. Stock refers to the size of the population at a
particular point in time. Flow refers to the number of entrances into (in-flow) and
exits from (out-flow) the population during a given time period. Most estimates of
the volume of the migratory flow have focused on in-flow. In-flow in turn may be
subdivided into gross in-flow and net in-flow. Gross in-flow is the total number of
entrances made during a given time period whereas net in-flow is the number of
persons entering during a given time period. Because an individual may enter the
country as an unauthorized migrant more than once in a single time period, net inflow is almost by definition smaller than gross in-flow. In contrast to in-flow,
relatively little attention has been paid to the size and components of the out-flow
of unauthorized migrants. Persons may exit unauthorized status through death,
emigration, deportation, or legalization. Out-flow is a critical component because
the majority of entrances are offset by exits, as indicated by estimates of net flow.
Observers who fail to account for out-flow risk highly exaggerated estimates of
the rate of growth of the unauthorized migrant population. More attention has been
paid to estimating net flow (in-flow minus out-flow). Net flow has typically been
estimated as the change in stock as it is estimated at two or more points in time
(Passel and Woodrow, 1987; Woodrow, Passel, and Warren, 1987).
Another conceptualization which is related to the idea of stocks and flows but
is analytically distinct is the notion of temporary or permanent migrants, or sojourners
and settlers, to use the more sociological distinction (Bean, Vernez, and Keely,
1989; Chavez, 1988). Here the reference is to the duration of stay in the destination
country, but especially to the migrant’s intended duration of stay (Roberts, 1995).
Such intentions have consequences because the kinds of immigration and settlement
policies that might be invoked in the cases of temporary and permanent migrants
are not necessarily the same (e.g., see Passel, 1986). Further complicating the
situation is that many temporary migrants undergo a transition to permanent migrant
status over time. Although it is important to keep in mind that temporary and
permanent migrants have a different sociological and policy significance, at another
level it is useful to think of these two kinds of migrants as differing only in their
durations of stay. At a given point in time, estimates of the stock of Mexican migrants
will include both permanent and temporary migrants, the latter of whom are
disproportionately likely to return to Mexico within short periods of time. One of
the challenges facing the estimation of stocks and flows of migrants, as we note
below, is to develop more complete information on the duration of stay distribution
of migrants, especially by sex, age at migration, and mode of entry. If such
information were available, it would be relatively straightforward to develop
estimates of stocks and flows of migrants. Of course, the sociological differences
(and their attendant policy implications) between migrants who intend short or
long durations of stay would nonetheless remain significant.
33
Based on the distinctions of mode-of-entry (EWI vs. overstayer) and intended
duration of stay, we may construct a four-fold classification of unauthorized entrants (see Figure 5). The groups represented by the boxes (bottom row) in this
classification are important because they have implications for policy. Much of the
historical and current debate in the United States about illegal migration derives
from differences in perceptions about which of the kinds of flows described by
these categories dominates the overall flow of migrants, thus affecting growth in
the stock of unauthorized migrants. During the 1970s, for example, many observers confused the concepts of stock and flow, mistaking evidence indicating large
numbers of entrances for a sizable stock of migrants. In effect, the error was to
assume that permanent EWIs substantially predominated over temporary EWIs,
when at that point in time the evidence indicated just the opposite was true. Now
immigration analysts debate the relative importance of the EWI versus the overstayer
flow, a debate that is not likely to be resolved until we can ascertain the relative
size of the temporary versus permanent (or short-term versus long-term) component of each flow. Thus, if almost all of the visa overstayers were found to return to
their countries of origin within two or three years of having violated the terms of
their visas, estimates of the stock of overstayers would consist primarily of temporary migrants, however numerous such persons might be at a given moment in
time. This scenario would have different policy implications than one in which
visa overstayers were generating large numbers of permanent migrants.
Approaches to the Estimation of Stock
Early efforts (during the 1970s and early 1980s) to determine the size of the
total unauthorized migrant population produced results that were highly speculative, ranged widely, and were usually much higher than analytic estimates (Keely,
1977; Siegel, et al., 1980, Tuirán, 1984). Despite methodological difficulties and
Unauthorized Entrants
EWIs
Permanent
EWIs
Visa Overstayers
Temporary
EWIs
Permanent
Visa Overstayers
Temporary
Visa Overstayers
Figure 5. Analytic Typology of Kinds of Unauthorized Entrants
Based on Mode of Entry and Intended Duration of Stay
34
persistently large ranges, more empirically-based and analytic studies produced
estimates of stock that failed to support the speculative assertions that there were
more than 6 million unauthorized migrants in the country. Some early estimates of
the Mexican unauthorized population also relied on Mexican census or survey data
as we note below.
Estimates of the size and growth of the unauthorized migrant population in the
late 1980s and 1990s attempted to address some of the shortcomings of previous
work. During the 1980s, the majority of these new studies employed a residual
method of one form or another. Residual methods provide an estimate and description
of the “enumerated” unauthorized migrant population, that is, the part of the
unauthorized population that is enumerated in the Census or represented in a sample
such as the Current Population Survey (CPS) (the unenumerated portion of the
population must be estimated by other means, as we discuss below). As noted in
the previous section, the enumerated unauthorized population is estimated as the
difference between the total foreign-born population enumerated in the Census or
the CPS and the legally resident population (total enumerated foreign born - legally
resident immigrants = enumerated illegally resident migrants). This computation
may be done separately by national origin, period of entry, age, sex, and, depending
on the level of detail available in estimates of the legal population, by state and
metropolitan area. Hence, a substantial amount of information about the enumerated
unauthorized migrant population may be produced by residual methods. Studies
that use a residual method are listed in Table 11. Most of these studies were conducted
by the Bureau of the Census. Except in the case of Heer (1979) and Warren (1982),
residual methods were generally not employed with data collected prior to the
1980s because the 1980 Census was the first decennial census in which a sizable
enumerated unauthorized migrant population could be detected through demographic
analysis (Fay, Passel, and Robinson, 1988).
Residual estimates of the enumerated unauthorized population are sensitive to
estimates of their two components, the total enumerated foreign born and the legally resident foreign-born population ( as discussed above). In the series of residual estimates made by Census Bureau researchers, the foreign-born population
enumerated in the Census or the CPS is routinely adjusted for errors associated
with respondents not reporting country of birth, misreporting citizenship status,
and misreporting nativity. The task of approximating the number of legally resident migrants presents greater difficulties. Because respondents are not asked about
legal status in the Census or the CPS, estimates of the legal immigrant population
must be obtained from external sources. Due to changes in the external data sources
available and changes in the legal population brought about by the IRCA amnesty
program, different methods have been developed to estimate the size and composition of the legal immigrant population, as noted above.
35
36
Estimation
Date
1970 - 1975
1979
1980
1980
1980
Nov., 1979
April, 1983
1980
June, 1986
June, 1988
Author(s), Date of
Publication or Release
Heer (1979)
Warren (1982)
Passel and Woodrow (1984)
Warren and Passel (1984)
Passel (1985b)
Passel and Woodrow (1987)
Warren and Passel (1987)
Woodrow, Passel and
Warren (1987)
Woodrow and Passel (1990)
Unauthorized migrants in CPS
Unauthorized migrants in CPS
Unauthorized migrants in 1980
Census
Unauthorized Migrants, total and
Mexican, age 14+
1980 Census
Estimates for SMSAs of
unauthorized residents in
Unauthorized migrants in
1980 Census
Unenumerated
unauthorized migrants
in the 1980 Census, by state
Unauthorized migrants in 1979
November CPS
Net flow of unauthorized migrants
(EWIs) from Mexico
Type or
Description
Residual Method 3
Residual Method 2
Residual Method 1
Residual Methods 1and 2
Residual Method 1
Residual Method 1
Residual Method 1
Residual Method 1
Residual Method 1
Method
Total: 1,906,000
Total: 3,158,000
Mexico: 2,200,000
Total: 2,057,000
Mexican: 1,131,000
1979: 1,273,000 (Mex.: 917,000)
1983: 2,093,000 (Mex.: 1,422,000)
Sum is consistent with national
estimates
931,000 Mexicans
Total: 2,060,000 (CA = 49.8%)
Mexican: 1,131,000 (CA = 67.5%)
Total: 1,250,000
Mexican: 734,000
82,300 - 232,000 per year;
Author’s favorite: 116,000 per yr.
Estimate
Table 11
Residual and Other Estimates of the Stock of the Unauthorized Migrant Population in the United States
37
Estimation
Date
Nov., 1989
April, 1990
1990
1990
1980
1990 and
Oct., 1992
Oct. 1996
Author(s), Date of
Publication or Release
Woodrow (1991a)
Woodrow (1992)
Clark, et. al. (1994)
Bean, King, and Passel
(1983)
Warren (1995)
INS (1997)
Total and Mexican-born
unauthorized migrants
Total and Mexican-born
unauthorized migrants
Mexican unauthorized migrants
Unauthorized migrants
in the 1990 Census
Published version of Woodrow
(1991a)
Total and enumerated
unauthorized migrant populations
Type or
Description
Total: 3.3 million (1.7 to 5.5 million)
1989 CPS: 2.05 million (1.1 to 2.0 million
if SAWs included),
1990 Census: 2.4 million (1.8 to 3.2
million)
Estimate
Constructive Method based
on CPS residual estimates,
Visa overstayers, and IRCA
non-applicants
Constructive Method based
on CPS residual estimates,
Visa overstayers, and IRCA
non-applicants
Sex-ratio, age distribution
assumptions
Data: Mexican Census
Total: 5 million
Mexican: 2.7 million
1990: Total: 2,600,000
Mexican: 1,009,000
Oct., 1992: Total: 3,400,000
Mexican: 1,321,000
1.5 - 3.8 million
(no more than 4 million)
Residual Method 3 with
1,975,000
different assumptions (include
half of SAWs in legal
population)
Residual Method 3, and
various assumptions about
undercount
Method
Table 11 (Continued)
After 1981, the Alien Registration Program was discontinued. As a result,
estimates of the legal alien population had to be constructed by projecting forward
the 1980 adjusted Alien Registration population to the appropriate year. For each
year of projection, numbers of new legal immigrants, refugees and other longterm legal nonimmigrants were added and numbers of emigrants and deaths due
to the legally resident foreign born were subtracted. The Census Bureau used this
method to estimate the unauthorized population enumerated in the CPS during
the 1980s up until the enactment of the IRCA legalization programs in 1988. These
studies include analyses of the April 1983 (Passel and Woodrow, 1987) and the
June 1986 CPSs (Woodrow, Passel, and Warren, 1987), which were the only CPS
data collected before 1988 that included information about nativity. These studies
conclude that by June 1986, about 3.158 million unauthorized migrants, 2.196
million of whom were born in Mexico, were detected by the CPS. More importantly,
by this time the Census Bureau had compiled consistent estimates of the
unauthorized population enumerated in the CPS from 1979 to 1986. Assuming
that the rate of undercoverage was consistent across the CPS samples, reliable
estimates of net growth of the unauthorized population could be made. The studies
indicate that the unauthorized migrant population grew during the early 1980s by
about 218,000 per year, and the Mexican-origin unauthorized population by about
115,000 per year. Due to uncertainties associated with assumptions about
emigration and disproportionate undercoverage, however, the authors conceded
that the annual net growth of the unauthorized population could have been in the
range of 100,000 to 300,000, with about half of the growth due to growth in the
Mexican-origin unauthorized population.
Most of the error associated with estimates that use this method is due to uncertainties associated with emigration rather than immigration or mortality. The
INS keeps accurate records of the number and types of legal immigrants. Also, the
component due to mortality is small in comparison to the other two components of
change, so the proportion of total error due to error in the number of deaths is small
(Himes and Clogg, 1992). However, the INS has not collected data about emigrants since 1957. During the 1980s, the Census Bureau routinely used a midrange estimate of 133,000 foreign-born emigrants per year. This approximation
was based on the results of research pertaining to the 1960s (Warren and Peck,
1980) and the 1970s (Warren and Passel, 1987). During the 1980s, attempts were
made to update estimates of the emigration component by analyzing special items
included in the CPS during the late 1980s that asked respondents about relatives
who emigrated (Woodrow-Lafield, 1996). Although the results of this work do not
contradict the estimate of 133,000, it also indicates that other estimates of the annual number of emigrants ranging from about 110,000 to 200,000 would be plausible. To the extent that the actual annual number of emigrants during the 1980s
38
were consistently higher than 133,000, the legal migrant population would have
been overstated and the enumerated unauthorized migrant population would have
been set too low. The opposite would be the case if the actual annual number of
emigrants had consistently been lower than 133,000. Because annual estimates of
emigration are subtracted from the legal alien population for each year the population is carried forward, the error associated with emigration increases with each
additional year. In other words, the longer the time data sources on the legal migrant population or emigration are not available, the greater the uncertainty associated with residual estimates.
Another source of error in estimates produced by the method relates to assumptions about undercoverage of the legal immigrant population. The method
assumes that all the legal noncitizens are enumerated. In addition, the method assumes that all immigrants who arrived since 1980—regardless of citizenship status—are represented in the CPS. The bias associated with this additional assumption most likely increases over time as the proportion of the immigrant population
who arrived after 1980 grows. The error due to this bias is increased even more for
the above cited studies because they analyzed CPS rather than census data and the
CPS has higher levels of undercoverage than the census (Woodrow, 1991). That is,
residual estimates of the enumerated unauthorized population are understated the
most when undercount rates of the legal population are the highest. Of course, if
the error associated with emigration leads to an overestimate of the unauthorized
population, then part or all of the underestimation due to assumptions about
undercount of the legal population may be canceled out.
Starting in 1987, about 1.7 million long-term unauthorized migrants and an
additional 1.3 million unauthorized special agricultural workers (SAWs) applied
for legalization under the amnesty provisions of the 1986 Immigration Reform and
Control Act (IRCA). As a result, post-1987 residual estimates of the unauthorized
migrant population have to be adjusted to account for this increase in the legal
population. In this variation of the residual method, the legal population is constructed in the same way as in the one above, only the number of IRCA legalized
migrants are added to the estimate of the legally resident foreign-born population.
Studies using this method include analyses of the June 1988 (Woodrow and Passel,
1990) and the November 1989 CPS files (Woodrow, 1990, 1991, 1992), and the
1990 Census (Woodrow, 1991; GAO, 1993; Clark, et al., 1994). The results of
these studies show that about 2.3 million (ranging from 1.8 to 3.2 million) unauthorized migrants were enumerated in the 1990 Census, of whom no more than 80
percent were born in Mexico. This research also indicates that had IRCA not taken
effect, the unauthorized population would have grown by roughly 200,000 annually between 1986 and 1990, reaching a size 70 percent larger in 1990 than was
observed. Most of this difference was due to the large numbers of Mexicans who
39
legalized under IRCA; Mexicans comprised more than 70 percent of the IRCA
legalized population (Woodrow and Passel, 1990).
Estimates produced by this approach may be inaccurate because it is unclear
what fraction of the SAW legalized population remained resident in the United
States after legalization. Many SAW applicants presumably were seasonal migrant
workers who spent a portion of each year in Mexico. Whether to include the SAW
population in estimates of the legally resident population is important because each
addition to the legal population results in a one-to-one decrease in the estimated
unauthorized population. Even though researchers tend to focus on the number of
SAWs who were resident in the United States at the time of the Census, it is more
important to focus on the number of SAWs who were actually enumerated in the
Census. The Census Bureau assumes that an insignificant number of SAWs were
enumerated in the Census or CPS. Hence, they do not include the 1.3 million SAWs
in estimates of the enumerated legally resident alien population (although they do
provide ranges of estimates that result from varying assumptions about coverage
of the SAW population).
Clark, et al. (1994) attempt to make estimates based on more plausible assumptions. They assume that in the SAW legalized population all pre-1984 entrants, all non-Mexicans, and about half of the remaining post-1984 entrants were
resident in the United States at the time of the 1990 Census. This amounts to 728,000
or about half of the SAW population. Clark, et al. (1994) include all 728,000 in
estimates of the legally resident population, resulting in an estimate of only 1.975
million enumerated illegals in 1990 (in comparison, the Census Bureau made a
“preferred” estimate of 2.390 million). Although it does seem implausible that no
SAWs were resident nor enumerated in 1990, the Clark, et al. estimate of 728,000
could be too high. Even if half of the SAW population were resident in the United
States in 1990, it is doubtful that more that 40 to 50 percent of this group were
enumerated. Migrant agricultural workers have the highest rates of undercount
among all groups, reaching 60 to 70 percent (Gabbard, Kissam, and Martin, 1993).
There is evidence that a large number of SAW applicants were not really farm
workers, plus there is no guarantee that farm workers in 1988 continued to be farm
workers in 1990. Hence, more SAWs may have been resident in the United States
in 1990 than many analysts have thought, and since many of the SAWs may have
been working outside agriculture, they may have had higher coverage rates than
has previously been assumed.
In sum, residual methods provide reliable, consistent estimates of the size and
growth as well as detailed descriptions of the resident unauthorized migrant
population. In comparison with earlier analytic studies, the studies that used residual
methods during the 1980s and early 1990s were more successful at describing,
quantifying, and reducing the range of error associated with their estimates.
40
Unfortunately, the range of error is likely to grow over time as information about
emigration and the size and geographical residence of the legal immigrant population
become increasingly out-of-date, and as other changes occur in the legal population,
such as those brought about by IRCA. Unless other methods for obtaining accurate
information about emigration or the legal immigrant population are developed,
residual methods will probably dominate the literature to a lesser extent in the
future than they did during 1980s. Another important limitation of residual estimates
is that they describe a selective part of the unauthorized population, namely the
portion that is probably least mobile and most permanently established. As we
describe below, other methods must be used to estimate the total and unenumerated
portions of the stock of the unauthorized migrant population.
Approaches to the Estimation of Flows
In comparison of estimates to stock, few speculative estimates have been made
about the rate of growth of the unauthorized population. Chapman (1976) guessed
that the population grew by 500,000 per year, and Reubens (1980) estimated an
annual growth of 600,000 during the 1970s. Despite empirically based analytical
evidence that the annual growth of the unauthorized population was considerably
less than the speculative estimate of 500,000, the media and others continued to
cite the number. As Passel (1985a:6) chided, “The figure of 500,000 per year is
widely used even though there is no strong empirical support for selecting this
figure over any other. It seems to be popular because it is a nice ‘round’ figure that
is easy for the public to accept.”
Analytic estimates of the volume of in-flow and net flow of the unauthorized
population tended to refer to different parts of the unauthorized population and
ranged widely. These studies are listed in Table 12. Garcia y Griego (1980), using
Mexican survey data on migration histories, estimated that the annual in-flow of
unauthorized migrants to the United States from Mexico in 1975 ranged from 75,000
to 284,000. Others used INS apprehensions data as a proxy for general patterns in
the level of flow of EWIs from Mexico (e.g., North, 1975; Frisbie, 1975). The
difficulties associated with using apprehensions data as a proxy for the flow of
EWIs are that (1) apprehensions data do not include those who succeed in evading
detection, and (2) apprehensions data count arrests, not individuals; arrest data are
potentially misleading because they include multiple arrests of the same person.
The INS (1976) attempted to estimate the component of fraudulent successful entries by conducting field studies at 15 Mexican border entry points and 10 major
international airports. Two teams of immigration inspectors were stationed at each
entry point and carried out careful inspections of entrants for fraudulent documents and intent to violate visa terms. Based on this work the INS concluded that
41
42
Estimation
Date
1960s1970s
1974-1976
1975
1970-1975
1978
April, 1980April, 1983
1979-1986
and
1980-1986
Author(s), Date of
Publication or Release
North (1975)
Chapman (1976)
U.S. Department of Justice,
INS (1976)
Heer (1979)
CENIET-Garcia y Griego
(1980)
Passel and Woodrow (1987)
Woodrow, Passel and
Warren (1987)
Net flow of unauthorized migrants
Annual net flow of unauthorized
migrants, age 14+
Unauthorized Mexican migrant
workers
Net flow of unauthorized migrants
(EWIs) from Mexico
Unauthorized migrants entering
with fraudulent documents or
intents to violate Visa terms
Non-immigrant Visa-overstays
Flow of unauthorized migrants
Type or
Description
740,000 failed to leave on time
since 1974; over 1,000,000 from
before 1974.
Rise in flow during the 1960s, but
not in the 1970s.
Estimate
Residual Methods 1 and 2
Residual Methods 1 and 2
Mexican 115,000 per year
1980-86: Total 176,000 per year
Mexican 170,000 per year
1979-86: Total 218,000 per year
100,000 to 300,000 per year
INS apprehensions; migration Net inflow 1975-1976:
histories of 822 Mexican
75,000-284,000 problems
males, 1973, prior to entry
Residual Method 1, CPS data 82,300-232,000 per year;
Author’s favorite: 116,000 per yr.
Thorough INS inspections at 500,000 successful fraudulent
border points and at 10 major entries
airports, Sept. 1975-Feb. 1976
Matched Visa entrance and
departure records of
non-immigrants
Apprehensions
Method
Table 12
Analytic Estimates of the Flows of the Unauthorized Migrant Population to the United States
43
Estimation
Date
Nov., 1986Sept., 1989
Nov., 1986Sept., 1988
1985-1988
1977-1988
Author(s), Date of
Publication or Release
Bean, Espenshade, White,
and Dymowski (1990)
Espenshade (1990)
Warren (1990)
Espenshade (1995a)
Gross flow of EWIs (Southern
border)
Non-immigrant Visa-overstays
by country of origin
Gross flow of unauthorized
Mexican EWIs (Southern border)
Net flow of EWIs (Southern
border)
Type or
Description
Estimate
Repeated trials model
INS matched arrival and
departure records
Repeated trials model
Correlation between apprehensions
and flow = 0.9; Flow = 2.2 * apps.
Annual number: 217,000 to 255,000
(fluctuated by year). Primary country
of origin is Mexico
Per month: 175,000 unauthorized entries
Total: 4,000,000 from 1986-1988
Data: INS apprehensions,
Apprehensions have seasonal pattern,
controlled for population in
have dropped post-IRCA, and have
Mexico at risk of migration
increased among women and children
(age 15-34), number of SAWs,
and wage and employment
ratios
Method
Table 12 (Continued)
there were 500,000 fraudulent entries into the United States in 1975, although these
estimates have been severely criticized because of small sample sizes and variable
rates of detection depending on the day of the week, the immigration inspector,
and point of entry (Keely, 1977).
Chapman (1976) attempted to measure the visa overstay component of the
in-flow of unauthorized migrants by matching INS records of nonimmigrant
visa entries and departures. He estimated that from 1974 to 1976, 740,000
nonimmigrants (about 250,000 annually) failed to leave the United States on
time. These estimates were almost certainly too high because they included
nonimmigrants who left the country but whose departure forms were never filed,
were lost, or otherwise never successfully matched with an arrival form. The
size of this error was probably large. At the time, the INS collected about 6
million entrance forms from nonimmigrants per year, and departure forms were
linked with arrival forms by matching the name of the nonimmigrant (Siegel,
et al., 1980).
Summed together, the estimates of in-flow of EWIs and visa overstayers easily matched and even exceeded the speculative estimate that the unauthorized population grew at a rate of 500,000 per year. However, analytic estimates of net flow
showed that the out-flow component of the unauthorized migrant migration stream
offset much of the in-flow component. Based on an analysis of CPS data, Heer
(1979) estimated that the unauthorized Mexican population grew by about 116,000
annually from 1970 to 1975. Although Siegel, et al. (1980) criticized the estimate
because of its large sampling error, they concluded on the basis of the study and
other evidence that much of the unauthorized migration to the United States appeared to be circular and was offset by return migration to Mexico.
Studies of flow published during the 1990s have exploited the availability
of new data and new estimation techniques. The INS has long matched arrivals
with departures, terming arrivals that do not match with departures apparent
overstays. The latest research using this data goes one step further by attempting
to eliminate system error in the data (Warren, 1990). System error refers to false
overstays. INS data for 12 countries which are assumed to have no overstays are
used to determine the extent of system error (Belgium, Netherlands Antilles,
Norway, Sweden, Kuwait, Saudi Arabia, Switzerland, Australia, New Zealand,
Surinam, Singapore and Finland). System error is computed separately by class
of admission. First, overstays are estimated for each country using the
Nonimmigrant Information System (NIIS). Next, system error is subtracted from
the rate of apparent overstay. The remainder is multiplied by the number of
expected departures to equal the estimated number of overstays. For estimation
by state of destination and age, a calculation was made for each category by
state or age. The rate of system error was adjusted to match those of the countries.
44
Nonimmigrant arrivals increased from 9.4 million in 1985 to about 14.3 million
in 1988. The annual number of overstays has fluctuated around 217,000-255,000
(increasing 12% in 1986 and dropping 7% in 1987 (following IRCA) and increasing
13% in 1988). The level of system error has dropped continually (10.3% in 1985 to
8.1% in 1988). North America has been the primary region of origin for overstayers
(with the most growth occurring among those from Mexico). The top five countries
of origin (Mexico, Haiti, the Philippines, Poland and India) were also among the
leading countries for application for legal residence under IRCA. Looking at the
geographic distribution of those overstaying their visa time limits, those states with
the largest foreign-born population also attracted the most overstays. Finally, Warren
finds that most overstays were between ages 15 and 44.
Two primary assumptions are associated with this estimation procedure: (1)
that there are few actual overstays from the 12 benchmark countries selected so all
apparent overstays from these countries are assumed to represent system error and
(2) that a single point estimate of system error applies to every country within a
category of admission. In addition, the estimates exclude immigrant students who
overstay and all those who enter the United States without inspection (EWIs). In a
modification of the procedure undertaken as a result of a GAO (1995) scrutiny of
the approach, system error was re-estimated on a airline-by-airline instead of country
basis. While the revision resulted in somewhat higher or lower figures for a few
countries, the overall result was nearly identical to the figures obtained using the
previous method.
Apprehensions data have also continued to be used as a way of roughly gauging undocumented migration flows (Jenkins, 1977; Fogel, 1982; Davila, 1986 and
Borjas, Freeman and Lang, 1987). Studies focusing on INS apprehensions data
published during the 1990s (Bean, et al., 1990; Espenshade, 1990; 1995a; Crane,
et al., 1990; Massey and Singer, 1995) have improved considerably over earlier
efforts by better controlling for the influence of contaminating variables. Some of
these studies also convert apprehensions into border crossings by assessing the
probability of getting caught and the population at risk of getting caught, thereby
adjusting for multiple apprehensions of the same person in the data (Passel, Bean
and Edmonston, 1990; Espenshade, 1995a). In order to gauge the influence of factors that affect flows across the border, these estimates rely on models with sets of
demographic, economic, and behavioral variables (the size of young adult population in Mexico (15-34); the number of legalized SAWs; relative wage and unemployment ratios; dummy variables for months to capture seasonality; the number
of officer hours and other measures of enforcement on the border for apprehensions) (Bean, et al., 1990).
Apprehensions data are limited because many unauthorized migrants are never
apprehended, others may be apprehended many times, and the volume of
45
apprehensions depends on the amount of effort expended by the INS to apprehend
border crossers. Researchers compensate by using some measure of the amount of
border patrol effort (Bean, et al., 1990; Jenkins, 1977; Fogel, 1982; and Borjas, et
al., 1987) and include measures of the population at risk for apprehension (Bean,
et al., 1990). Espenshade (1990, 1995a) takes the analysis one step further by using
a repeated trials model that “captures the phenomenon that, once arrested by the
U.S. Border Patrol and taken back across the Mexican border, most undocumented
migrants are likely to keep trying to enter the United States until they succeed”
(Espenshade, 1990:175). Making use of INS data on the number of repeaters to
estimate the probability of apprehension, and then using this to convert the number
of apprehensions to estimates of the numbers of crossers. Espenshade constructs a
time series on the monthly flow of undocumented migrants. He arrives at an estimate
for the period January 1977 to September 1988 of about 175,000 per month, or a
total inflow of 20.6 million undocumented migrants (that is, gross flow of 20.6
million). In another repeated trials study, Massey and Singer (1995) utilize INS
apprehensions data combined with data from surveys of migrants, which enable
them to estimate return migration. They arrive at an estimate of net flow for the
period 1965 to 1989 of 5.2 million (or an average of about 18,000 per month, net).
Further Issues Affecting Estimates
of Stock and Flow
The aforementioned results on the large differences in measurements of gross
and net flows underscore the importance of data on return migration to Mexico for
stock and flow estimates, including information on the length of time migrants
stay in the United States. This is a critical area where more research is needed.
Another area needing research involves the question of the degree of
underenumeration of the unauthorized population. In what follows in the rest of
this section, we discuss these issues and present new evidence on both patterns of
return migration and underenumeration.
Return Migration and Duration of Stay Issues
The distribution of the length of duration of stay in the United States among
unauthorized migrants by mode of entry and the change in this distribution over
time are crucial factors in understanding the significance of various estimates of
the size of the unauthorized migrant population. If almost all EWIs were circular
migrants staying only a short time, and if almost all visa overstayers returned to
their countries of origin within a couple of years or so, the policy significance of
unauthorized migration would be greatly different than if either EWIs or visa
46
overstayers, or both, contained substantial fractions of long-duration migrants.
Similarly, long-duration migrants (say those who stay 10 to 20 years or more) but
who then return to their countries of origin are different yet again in their implications
for policy from migrants who stay permanently.
At present, very little is known about the distribution of duration of stay of
EWIs and visa overstayers (although data on this variable are now available for the
sub-group of EWIs who have returned to Mexico from the studies conducted by
Massey and his colleagues) (e.g., Massey and Espinosa, 1997; Lindstron, 1996).
Also, information on the duration of stay of visa overstayers has reportedly been
calculated but not released by the INS. One of the reasons duration information is
important is because migrants with different durations of stay exert different demands on public benefits. At the extremes, if the periodic flow of EWIs and visa
overstayers were each very large, the cumulative stock of unauthorized migrants in
the United States at any one point in time could be very sizable sizable even if all
durations of stay were relatively short (i.e., even if all migrants were temporary). If
EWIs were to exhibit typically longer durations than visa overstayers, they would
contribute more to the stock of unauthorized migrants on that count alone.
What does the available evidence suggest about the comparative distributions
of duration of stay among EWIs and visa overstayers? In the case of EWIs, almost
all of whom are from Mexico, several pieces of evidence point to increasing durations of stay over the past 15 to 20 years: (1) increasing proportions of entire families, including women and children in the Mexican flow (Bean, et al., 1990; Woodrow
and Passel, 1990; Cornelius, 1992); (2) possibly decreasing rates of
underenumeration of the undocumented Mexican-born population in official U.S.
Censuses and surveys, as noted below, a trend that could result from increasing
proportions of migrants with longer durations of stay, especially given that census
undercount rates in general have not been declining over the same period (Robinson,
et al., 1993); and (3) ethnographic studies whose results indicate that Mexican
migrants now embarking for the United States show longer intended durations of
stay than prior migrants (Cornelius, 1992). Unless a comparable shift has occurred
in the duration distribution among overstayers, this would have the effect of raising the proportion of the illegal stock attributable to EWIs. In the case of visa
overstayers, the only relevant evidence to our knowledge is Warren’s (1995) finding that when overstayers were traced for a year or two longer than the one year
that is typically examined for purposes of defining an overstay, about 46 percent
had either converted their status or returned to their country of origin. This suggests that if they were followed a bit longer, the vast majority might be found to
have converted their status or returned.
Even though durations of stay may be increasing among EWIs, many may still
eventually return to Mexico (a pattern we might term long-term circular migration),
47
particularly in response to life course and economic opportunity factors. Evidence
of such a pattern would also have significant policy implications. Tables 13 to 15
present information on the extent of cohort succession among Mexican-born persons
based on results from the 1970, 1980, and 1990 U.S. Censuses and the 1994/95
CPSs. Does the evidence in these tables indicate that Mexican migrants tend to
return to Mexico after having spent time in the United States, a phenomenon we
would expect to be more likely among the undocumented? Because there were
hardly any undocumented migrants enumerated in the 1970 Census, we would not
anticipate evidence of cohort attrition beyond what we would expect based on
mortality in the 1980 data, and this is in fact what we observe. In the cases of 1990
and 1994/95 data, however, evidence of cohort attrition emerges among migrants
who have reached age 45 at the end of the period. Since there is no known reason
to think this occurs because of migration to some other country, it is reasonable to
think it stems from return migrations to Mexico. This phenomenon, of course,
would reduce the stock of Mexican EWIs compared to the case where long-term
circular migration did not occur and most migrants were permanent.
Underenumeration Issues
Because residual techniques generate estimates of the enumerated portion of
the unauthorized Mexican population, such approaches underestimate the true size
of this population at any given point in time by an amount equal to the size of the
unenumerated portion of the population. In order to develop estimates of the total
size and growth of the unauthorized Mexican population, it is thus important that
methods be developed for assessing the size and growth of the unenumerated portion of the population. A number of different researchers have made and continue
to make assumptions about the underenumeration rate in the unauthorized migrant
population that are not substantially empirically-based. For instance, some have
argued that the undercount rate for illegals must be at least as high as the highest
rate among native-born groups. On the basis of this logic, some analysts argue that
undercoverage must be as high as 20 percent, the rate exhibited by native-born
African-American males aged 20-29 (e.g., Passel, Siegel, and Robinson, 1982).
Others have argued that the undercount rate in the 1990 Census may be at least as
high as it was in the 1980 Census (Woodrow, 1991). However, if the unauthorized
migrant population were more settled and less concentrated in agricultural occupations in 1990 than in 1980, then the undercount rate in 1990 might be lower than it
was in 1980.
Evidence about the size of the unenumerated portion of the unauthorized population for the census years 1980 and 1990 has been obtained by employing one of
two different approaches. The first involves direct attempts to estimate first the
48
Table 13
Components of Change from 1970 to 1980 in the Mexican-born Population
Due to Immigration, Mortality, and Other Causes
Population
Components of Change 1970 to 1980
Increase
Due
To Immig’n
(4)
Decrease
Due
To Mortality
(5)
Other
(6) =
(3)-(4)-(5)
Sex, Age in 1980
1970
(1)
1980
(2)
Change
1980-1970
(3) = (2)-(1)
Both Sexes, Total
759,711
2,199,221
1,439,510
1,270,246
-90572
259,836
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
–
–
15,084
31,459
41,926
116,503
138,300
118,238
94,431
203,770
55,325
119,309
148,775
214,195
312,309
547,228
315,402
191,476
128,407
166,795
55,325
119,309
133,691
182,736
270,383
430,725
177,102
73,238
33,976
-36,975
55,325
119,309
124,540
162,857
243,658
350,977
127,323
50,734
22,159
13,364
0
0
-62
-149
-376
-1,374
-2,142
-4,393
-8,582
-73,495
0
0
9,213
20,028
27,101
81,122
51,921
26,897
20,399
23,156
Males, Total
371,463
1,158,765
787,302
695,567
-53,626
145,361
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
–
–
7,749
15,962
20,878
57,458
64,532
57,683
48,949
98,252
28,513
61,963
75,678
117,785
177,796
300,934
162,660
93,961
65,546
73,929
28,513
61,963
67,929
101,823
156,918
243,476
98,128
36,278
16,597
-24,323
28,513
61,963
63,201
90,773
142,505
199,159
70,031
24,478
9,949
4,995
0
0
-37
-101
-275
-998
-1,340
-2,790
-5,768
-42,316
0
0
4,765
11,151
14,688
45,315
29,437
14,590
12,416
12,998
Females, Total
388,248
1,040,456
652,208
574,679
-36,946
114,475
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
–
–
7,335
15,497
21,048
59,045
73,768
60,555
45,482
105,518
26,812
57,346
73,097
96,410
134,513
246,294
152,742
97,515
62,861
92,866
26,812
57,346
65,762
80,913
113,465
187,249
78,974
36,960
17,379
-12,652
26,812
57,346
61,339
72,084
101,153
151,818
57,292
26,256
12,210
8,369
0
0
-25
-48
-100
-376
-802
-1,602
-2,814
-31,179
0
0
4,448
8,877
12,412
35,807
22,484
12,306
7,983
10,158
49
Table 14
Components of Change from 1980 to 1990 in the Mexican-born Population
Due to Immigration, Mortality, and Other Causes
Population
Sex, Age in 1990
Both Sexes, Total
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
Males, Total
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
Females, Total
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
50
Components of Change 1980 to 1990
1990
(2)
Change
1990-1980
(3) = (2)-(1)
Increase
Due
To Immig’n
(4)
Decrease
Due
To Mortality
(5)
Other
(6) =
(3)-(4)-(5)
2,199,221
4,298,014
2,098,793
2,144,919
-146,551
100,425
–
–
55,325
119,309
148,775
214,195
312,309
547,228
315,402
486,678
102,388
155,561
203,705
381,253
650,539
1,239,616
749,645
393,338
209,278
212,691
102,388
155,561
148,380
261,944
501,764
1,025,421
437,336
-153,890
-106,124
-273,987
102,388
155,561
155,913
255,960
495,186
657,455
189,441
78,033
33,412
21,570
0
0
-158
-441
-1,097
-5,688
-7,594
-9,267
-14,280
-108,027
0
0
-7,375
6,425
7,675
373,654
255,489
-222,656
-125,256
-187,530
1,158,765
2,369,514
1,210,749
1,233,235
-83,211
60,725
–
–
28,513
61,963
75,678
117,785
177,796
300,934
162,660
233,436
52,447
78,906
105,632
216,179
396,386
720,819
405,138
200,583
99,858
93,566
52,447
78,906
77,119
154,216
320,708
603,034
227,342
-100,351
-62,802
-139,870
52,447
78,906
81,144
151,736
314,872
387,207
103,226
40,369
14,804
8,524
0
0
-93
-297
-796
-4,476
-5,548
-6,109
-9,074
-56,818
0
0
-3,932
27,767
6,632
220,303
129,664
-134,611
-68,532
-91,576
1,040,456
1,928,500
888,044
911,684
-63,340
39,700
–
–
26,812
57,346
73,097
96,410
134,513
246,294
152,742
253,242
49,941
76,655
98,073
165,074
254,153
518,797
344,507
192,755
109,420
119,125
49,941
76,655
71,261
107,728
181,056
422,387
209,994
-53,539
-43,322
-134,117
49,941
76,655
74,769
104,224
180,314
270,248
86,215
37,664
18,608
13,046
0
0
-65
-144
-301
-1,211
-2,046
-3,158
-5,206
-51,209
0
0
-3,443
3,648
10,423
153,350
125,825
-88,045
-56,724
-95,954
1980
(1)
Table 15
Components of Change from 1990 to 1995 in the Mexican-born Population
Due to Immigration, Mortality, and Other Causes
Population
Sex, Age in 1995
1990
(1)
Components of Change 1990 to 1995
1995
(2)
Change
1995-1990
(3) = (2)-(1)
Increase
Due
To Immig’n
(4)
Decrease
Due
To Mortality
(5)
Other
(6) =
(3)-(4)-(5)
Both Sexes, Total
4,766,014
6,669,468
1,903,454
1,707,618
-99,031
294,867
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
–
113,537
172,500
225,886
422,767
1,463,595
1,119,252
600,093
313,748
334,637
112,349
296,585
302,377
447,095
895,238
2,022,661
1,285,707
655,699
336,475
315,282
112,349
183,048
129,877
221,209
472,471
559,067
166,454
55,606
22,727
-19,355
112,349
198,907
124,975
219,920
404,402
411,641
1,436,578
552,367
253,423
11,187
0
-151
-129
-480
-1,676
-7,525
-8,693
-8,935
-11,354
-60,089
0
-15,708
5,031
1,769
69,745
154,951
31,490
9,304
8,739
29,547
Males, Total
2,627,524
3,720,895
1,093,371
9,721,378
-58,249
179,482
–
58,158
87,498
117,134
239,718
879,166
623,849
318,102
154,746
149,154
68,095
166,829
163,080
259,654
530,888
1,164,056
715,896
346,287
156,329
149,781
68,095
108,671
75,582
142,520
291,169
284,890
92,047
28,186
1,583
627
68,095
116,356
72,411
134,184
238,671
210,175
97,404
18,442
8,252
8,148
0
-88
-76
-336
-1,313
-6,146
-6,581
-6,082
-7,122
-3,050
0
-7,597
3,247
8,672
53,811
80,861
1,224
15,826
453
22,984
2,138,490
2,948,573
810,083
735,480
-40,782
115,385
–
55,379
85,002
108,752
183,049
584,428
495,404
281,991
159,002
185,483
44,254
129,756
139,297
187,441
364,350
858,605
569,811
309,412
180,146
165,501
44,254
74,377
5,425
78,689
181,302
274,177
74,407
27,421
21,144
-19,983
44,254
82,551
52,564
85,736
165,731
201,466
46,253
36,795
17,091
3,039
0
-62
-53
-144
-363
-1,379
-2,112
-2,853
-4,232
-29,584
0
-8,112
1,783
-6,903
15,934
74,090
30,266
-6,521
8,286
6,562
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
Females, Total
0-4
5-9
10-14
15-19
20-24
25-34
35-44
45-54
55-64
65+
51
undercount rate through comparisons of U.S. Census results with external data
about small or localized populations, such as school enrollment records, in-depth
survey results, and the findings from ethnographic field research. Estimates of the
rate of undercount are then applied to the estimates of the size of the unauthorized
population enumerated in the Census in order to approximate the size of the entire
unauthorized population. The second approach entails first making independent
assessments of the entire unauthorized migrant population or national origin groups
within the population based on data sources and methods that are thought to be less
sensitive to undercount, and then comparing these estimates with the enumerated
population in order to estimate the rate of undercount. The results of both of these
approaches are reviewed below, first with respect to the 1980 Census enumeration
and then the 1990 Census enumeration.
Direct examinations of the level of undercount indicate that between 20 and
50 percent of the stock of unauthorized residents appeared to be missing from the
1980 Census enumeration. One study compared Los Angeles public school
enrollments with estimates of families with school-aged children in the 1980 Census
(Muller and Espenshade, 1985) (see Table 16). The results indicated that nearly all
families in Los Angeles were enumerated, including families of unauthorized
migrants. These results are consistent with the observation that the census is better
at enumerating settled populations such as unauthorized migrant families than single
migrants. The results of the study also suggested that the undercount rate of the
entire unauthorized population was probably no greater than 50 percent. This view
was substantiated by the results of a survey of Mexican adults living in Los Angeles
County (Heer and Passel, 1985, 1987). Foreign-born respondents were asked whether
they were legal residents and if so, to show the interviewer their “Green Card” or
equivalent evidence of legal status. Foreign-born respondents who indicated they
were undocumented or failed to show evidence of legal status were enumerated as
unauthorized migrants. Comparisons of the results of the survey with the number
of unauthorized Mexican migrants enumerated in the 1980 Census (Passel, 1985b)
suggested that the undercount rate among Mexican unauthorized migrants was
probably no greater than about 44 percent (Passel, 1985a; Passel and Robinson,
1988) (See Table 17).
Indirect evidence of undercoverage suggests a narrower range of undercount
for the unauthorized population, falling roughly between 30 and 40 percent. As
noted above, Bean, King, and Passel (1983) attempted to estimate the number of
Mexicans who had emigrated to the United States by analyzing the age and sex
composition of the population enumerated in the 1980 Mexican Census. Due to
uncertainties about the patterns of undercount in the Mexican Census and the
age-sex composition of the emigrant population, Bean, et al. (1983) concluded
that the number of unauthorized Mexicans living in the United States could be as
52
53
Estimation
Date
1980
1980
1980
1980
1980
1980
1980
1980
Author(s), Date of
Publication or Release
Bean, King, and Passel
(1983)
Keely (1983)
Heer and Passel (1985)
Muller and Espenshade
(1985)
Passel (1985a)
Bean, King, and Passel
(1986)
Passel (1986)
Heer and Passel (1987)
See Heer and Passel (1985)
Undercount rate in 1980 Census
for the unauthorized population
Mexican unauthorized migrants
Mexican unauthorized migrants
Families in Los Angeles
Adult Mexican unauthorized
migrants in Los Angeles County,
Males: 18-44; Females: 18-39
Undercount rate in 1980 Census
for the unauthorized population
Mexican unauthorized migrants
Type or
Description
Expert opinion
Revision of Bean, et. al. (1983)
Revision of Bean, et. al. (1983)
Compared Los Angeles school
enrollment data with Census
estimates in Los Angeles
Survey on legal status in
Los Angeles
Expert opinion
Data: Mexican Census
Sex-ratio, age distribution
assumptions
Method
Table 16
Studies with Implications for Underenumeration
no more than 50% undercount
1.5 - 2.8 million
1.9 million
1980 Census enumerated most
families in Los Angeles
44% undercount
33% - 50% undercount
1.5 - 3.8 million
(no more than 4 million)
Estimate
54
Estimation
Date
1980
1980
1990
1990
1990
Author(s), Date of
Publication or Release
Passel and Robinson (1988)
Borjas, Freeman, and Lang
(1991)
Woodrow (1991)
GAO (1993)
GAO (1993)
Undercount rate in 1980 Census
for the unauthorized population
Total Mexican unauthorized
migrant population
Total unauthorized migrant
population
Total Mexican unauthorized
migrant population
Total unauthorized migrant
population
Type or
Description
Review of ethnographic studies
Projection of 1980 Mexican
Census population to 1990
Projection from 1980 Estimate
to 1990
Analysis of deaths to
Mexican-bornpersons
Revision of Bean, et. al. (1983)
Method
Table 16 (Continued)
25% undercount, most estimates
fell between 5% and 28%
2.7 million
3.3 million (point estimate)
1.9 million
Total: 2.5 to 3.5 million
Mexican: 1.9 million
Estimate
Table 17
Direct and Indirect Estimates of the Undercount for the Unauthorized
Migrant Population in 1980 and 1990 U.S. Censuses
Estimated Unauthorized Pop’n
(in millions)
1980 Census
Direct Estimates of Undercount
Heer and Passel (1985, 1987);
Passel (1985); Passel and
Robinson (1988)
Indirect Estimates of Undercount
Bean, et. al. (1983)
Revisions of Bean, et. al. (1983)
Passel (1985)
Bean, et. al. (1986)
Passel and Robinson (1991)
Borjas, Freeman and Lang (1991)
1990 Census
Direct Estimates of Undercount
GAO (1993)
Indirect Estimates of Undercount
GAO (1993)
Woodrow (1991)
Warren (1995)
Undercount
Percentage
Total
Mexican-born
Total
Mexican-born
3.4-3.7a
2.0a
40-45%
44%
na
1.5-3.8
na
25-70%b
na
na
2.5-3.5
na
1.9
1.5-2.8
1.9
1.9
na
na
18-42%
na
40%b
25-60%b
40% b
40%b
3.2a
2.6a
25%
25%
3.4
3.3
1.0
2.7
29%b
27%b
-92%b
30%b
2.6
8%b
na: estimate not available.
a
Implied population based on estimate of undercount (see note below).
b
Implied undercount rate based on estimate of population (see note below).
Note: The implied population and undercount rates are based on the assumption that 2.1
million unauthorized migrants (1.1 million unauthorized Mexicans) were enumerated in
the 1980 Census, and that 2.4 million (1.9 million Mexicans) were enumerated in the
1990 Census.
low as 1.5 million and as high as 3.8 million. Comparing this range with the number
enumerated in the 1980 U.S. Census—1.131 million (Warren and Passel, 1987)—
the Bean, et al. (1983) estimate implies an undercount between 25 and 70 percent.
However, residual estimates of the Mexican unauthorized population enabled
researchers to narrow the range of assumptions used in this analysis (Bean, King,
and Passel, 1986; Passel, 1985a; Passel and Robinson, 1988). The results of these
revisions indicated that there were probably as few as 1.5 million to 1.9 million
unauthorized Mexicans migrants in 1980. Assuming that Mexicans comprise about
55
60 percent of the unauthorized population, this suggests that between 2.5 and 3.2
million unauthorized migrants were living in the U.S. in 1980. A comparison of
these estimates with the approximation of the enumerated unauthorized population
suggests an undercount rate of 25 to 40 percent among Mexicans and 18 to 36
percent among all unauthorized migrants.
Using a different approach, Borjas, Freeman, and Lang (1991) analyzed vital
statistics data to determine the number of unauthorized immigrants missed in the
1980 Census. The method they used is similar to that used by Robinson (1980),
except that it yields more precise results because it employs data on the number of
deaths to Mexican-born persons residing in the United States (such data became
available in 1984 when vital statistics began to record place of birth on death certificates). The methodology used by Borjas, Freeman, and Lang rests on the assumption that (1) all deaths to illegally and legally resident Mexican-born persons
that take place in the United States are recorded in the U.S. vital statistics and (2),
that the Mexican-born population experiences age specific death rates that are quite
similar to those experienced by the U.S. native-born population. If these assumptions hold, then the total Mexican-born population living in the United States may
be approximated by dividing the number of deaths to Mexican-born persons by the
death rate. By comparing this estimate with the number of Mexican-born persons
enumerated in the 1980 Census, the number of unenumerated Mexican-born persons can then be estimated. Borjas, Freeman, and Lang’s results indicate that the
number of unenumerated unauthorized Mexicans in 1990 was about 800,000. They
add this to Warren and Passel’s estimate to yield a total of 1.9 million unauthorized
migrants from Mexico, which implies a 40 percent undercount rate. The results of
this method tend to be highly sensitive to the underlying assumptions. Nevertheless, if the effects of its limitations could be minimized, the method has potential
because it is empirically based, it can provide national level results, and it can be
used to obtain annual estimates of the unauthorized population by age, sex, and
country-of-origin, as we demonstrate below in an application to the 1990 Census
enumeration of unauthorized Mexican-born male and female migrants.
To summarize, the results of undercount studies as well as comparisons of
external estimates with estimates of the enumerated unauthorized population suggest that at least 60 percent of unauthorized residents were enumerated in the 1980
Census. This implies that there were at most about 3.4 million unauthorized migrants and 1.9 million unauthorized Mexican migrants living in the United States
in 1980.
In the case of the 1990 Census enumeration, both direct and indirect evidence
suggest that the undercount rate for the unauthorized migrant population was lower
than it was in 1980. The direct evidence comes from a series of ethnographic studies
conducted by researchers working with the Census Bureau. The main purpose for
56
conducting these studies was to gain qualitative information about the causes of
undercount, although the results of the research can also be used to shed light on
undercoverage rates among various populations. The ethnographic evaluations were
conducted in 29 different neighborhoods across the United States and Puerto Rico,
each of which contained about 100 households. These 29 neighborhoods were selected because they were thought to contain large concentrations of difficult-to-enumerate populations. Experienced ethnographers made an effort to become familiar
with the households and household members who lived within the sample area by
accessing informal networks and gaining information about the actual residences of
people. Their assessments of the numbers of residents were compared with the official Census counts for the sample areas. The results of the comparisons showed that,
among those living in areas containing large concentrations of unauthorized migrants, the undercount rate was at most 25 to 30 percent. One area, Long Island, had
an undercount rate as high as 72 percent, but this result was not typical. The other
areas showed undercount rates as low as or lower than 28 percent, and five areas had
undercount rates less than 18 percent (GAO, 1993; de la Puenta, 1993).
Indirect evidence of the undercoverage of the unauthorized population in 1990
comes from only a few studies. Although Warren (1995) produces estimates of the
entire unauthorized population in 1990, his estimates appear too low and cannot be
relied upon. For instance, he puts the total Mexican-born unauthorized population
at 1 million, which is 92 percent lower than the residual estimate for 1990 (GAO,
1993). Woodrow (1991) makes a “point estimate” of the illegally resident population in 1990 of about 3.3 million (assuming a 25 percentage undercount). Woodrow
(1991) constructs this estimate by projecting forward the estimated 1980 illegally
resident population to 1990, adjusting for net growth during the 1980s and legalizations due to the amnesty provisions of IRCA.
Another study showing indirect evidence of the undercount rate in 1990 was
conducted by GAO (1993) in consultation with Corona Vasquez (1991). By comparing the Mexican population enumerated in the Mexican Census in 1980 with
those enumerated in the 1990 Mexican Census, Corona Vasquez (1991) estimated
that 1.5 to 3 million Mexicans emigrated during the decade. By adjusting this estimate for differential undercount and legal migration to the United States, GAO
(1993) concluded that about that about 2.7 million unauthorized Mexicans were
present in the United States in 1990. Assuming that Mexicans comprise about 80
percent of the total unauthorized migrant population (based on the 1989 CPS residual estimates), GAO puts the total unauthorized migrant population at 3.4 million. Like the results obtained from the ethnographic studies, these two estimates
imply an undercount rate of about 30 percent. This level of undercoverage implies
an unauthorized population of about 3.4 million (2.7 million Mexican unauthorized migrants) in 1990.
57
In what follows, we apply the “death registration” method used by Borjas,
Freeman, and Lang (1991) to obtain another estimate of the total illegally resident
Mexican population and the underenumeration rate for 1990. One of the drawbacks of the death registration method is that it is sensitive to its underlying assumptions. Nevertheless, if the data used to produce the final estimates is carefully
selected, the method can be used to obtain annual estimates of the total size of the
unenumerated unauthorized population by country of origin.
We use the method to produce a series of estimates of the number of
unenumerated unauthorized Mexican-born persons living in the United States in
1990. An estimate is made for several combinations of assumptions regarding the
numbers of deaths, different mortality schedules, and sizes of the enumerated
Mexican-born population. Table 18 presents estimates of the unenumerated unauthorized Mexican-born population, the total unauthorized population, and the implied undercount rate for each of several combinations of underlying assumptions.
The estimates of the total unauthorized Mexican migrant population range from
2.1 million to 2.9 million, with the interquartile range spanning 2.1 million to 2.6
million. The undercount rates corresponding with the interquartile range of estimates ranges from only 14 to 26 percent. The highest estimate of 2.9 million unauthorized migrants implies an undercount rate of only 34 percent. The estimates of
the underenumeration rate are higher for males, among whom as many as 40 percent may not have been enumerated. Finally, we note that of the three underlying
assumptions, those pertaining to the mortality schedule and the enumerated population tend to exert the greatest influence on the estimates.
In conclusion, the death registration method produces estimates of the
underenumeration rate that correspond with other evidence about undercount.
Namely, the underenumeration rate for unauthorized Mexican migrants in 1990
appears not to be as high as it was in 1980, most likely is no greater than 35 percent
and may even be as low as 15 to 25 percent. In addition, the results corroborate
other evidence that the female unauthorized migrant population is better represented in the U.S. Census enumeration than the corresponding male population.
The results also show that the death registration method produces estimates that
are sensitive to their underlying assumptions. Although the method has a great deal
of potential for use in the future, the quality of the estimates could be greatly improved if better information about the mortality rates experienced by the foreignborn population and the enumerated population were available.
Estimates Based on Mexican Data
We are aware that there are is great variety of methodological and conceptual
difficulties that have to be addressed in order to arrive at more precise and up to
58
59
168
77
227
101
158
64
180
84
260
120
186
79
313
487
67
200
979
821
558
598
300
447
200
899
627
677
361
510
241
Total
1,329
1,447
1,595
1,235
1,818
1,752
1,580
1,470
1,298
1,389
1,235
1,818
1,642
1,515
1,339
1,423
1,261
Males
892
948
990
873
1,069
977
886
1,036
909
967
873
988
893
1,069
929
994
888
Females
Estimate (in 1,000s)
2,221
2,394
2,585
2,108
2,887
2,728
2,466
2,506
2,208
2,355
2,108
2,806
2,534
2,584
2,268
2,418
2,149
Total
Total Unauthorized Population
17.3
24.0
31.1
11.0
39.5
37.3
30.4
25.2
15.3
20.9
11.0
39.5
33.1
27.5
17.9
22.8
12.8
Males
9.3
14.6
18.3
7.3
24.3
17.2
8.7
21.9
11.1
16.3
7.3
18.2
9.4
24.3
12.9
18.7
8.9
Females
14.1
20.3
26.2
9.5
33.9
30.1
22.6
23.9
13.6
19.0
9.5
32.0
24.7
26.2
15.9
21.1
11.2
Total
Percentage Undercount
See Table 3 in Volume 2, page 561, for various estimates of the number of deaths, mortality schedules, and the enumerated population.
83
139
181
653
481
371
199
290
136
719
543
416
240
324
162
25th Percentile
230
50th Percentile (Median) 348
75th Percentile
496
C1
C2
C1
C2
C1
C2
C1
C2
C1
C2
C1
C2
64
260
M1,
M1,
M2,
M2,
M3,
M3,
M1,
M1,
M2,
M2,
M3,
M3,
Females
136
719
D1,
D1,
D1,
D1,
D1,
D1,
D2,
D2,
D2,
D2,
D2,
D2,
Minimum
Maximum
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Males
Population Est. (in 1,000s)
M. Mortality Schedule
C.Enumerated Pop’n
Unenumerated Unauthorized
D. Number of Deaths
Assumptions About:
Table 18
Various Estimates of the Unenumerated Unauthorized Mexican-born Population and Percentage Undercount
date estimates of the different modalities of Mexican migration to the United States.
In addition to the difficulties in quantifying migration under any circumstances,
the very nature of the movement towards the United States complicates the process. Among the most important factor that cloud it is the surreptitious character of
much of it, the migrant population’s constant renewal, the indeterminate length of
migrant’s stay in the U.S. and the considerable number of people who return to
Mexico, even after long residence abroad.
As we mentioned earlier, measurements carried out in the United States have,
among others, two systematic shortcomings: the first one is the difficulty of counting
unauthorized migrants, that because of their surreptitious nature avoid detection; the
second one is that it is not possible to identify those migrants who go back to Mexico,
which can be either “legal” (have not been naturalized yet) as well as unauthorized.
These shortcomings are reflected in the underrepresentation of Mexican migrants in the statistical registers of the Immigration and Naturalization Service, as
well as in the Census undercount and in household surveys (in particular the Current Population Survey, CPS). This situation has lead researchers, to make important corrections and adjustments to the original figures by using indirect methods
and residual techniques.
On the other hand, the estimates carried out in Mexico face the great difficulty
that migrants are not found in their place of origin, either because they are living or
sojourning in the United States or because they are on their way there. This feature
has restricted the options available to researchers and government statisticians to
two methodologies. The first one involves direct measurements from retrospective
questions in household surveys that identify labor, permanent and return migrants
as well as direct measurement of migration flows through specialized methods for
finding, counting and interviewing those either on their way to work or on their
way from working in the United States.
The second uses indirect methods, which rely on incomplete or deficient information to estimate a population of interest. When combined with other data,
this information can be used to generate two different databases: one that supposedly contains or includes the migrants that are headed toward the United States (P
+) and another that excludes them (P -). The difference, or residual [ (P +) - (P -) ]
is attributed to migration. Conceptually, the residual is composed of many kinds of
people, which means that the resulting estimate may erroneously include some
individuals who have not really migrated, or may exclude some people who have.
In general, these approaches have generated plausible results that are consistent
with the demographic dynamics of the Mexican population and generally agree
with obtained in the United States. This section presents the results of efforts carried out for this project to estimate Mexican migration to the United States based
on Mexican data from the 1990s.
60
Direct Measurement Efforts
The National Survey on Demographic Dynamics
Since the late 1970s, Mexico has carried out various household sampling surveys
with the goal of using direct measures to quantify how many migrants move to the
United States (for example, the Demographic Survey of Baja California, the
Migration Survey in Zacatecas, etc.). The 1992 ENADID (the Spanish acronym),
which is the most up-to-date version of these surveys and is used in the country for
mid-decade enumerations, improves over these earlier surveys in several important
ways. Among these are the following: a) its national coverage; b) its utilization of
a considerable sample size (64,000 housing units throughout the country), which
permits the use and interpretation of data on a federal scale, c) and its inclusion of
various foci, in certain complementary measures, to quantify some of the diverse
modalities of the migratory phenomenon (INEGI, 1994).
The ENADID provides a basis for classifying certain Mexican residents as
“labor migrants” (people aged 12 years or older who have worked or looked for
work in the United States) and others as “return migrants” (people who were
habitual reside in the United States, but at the time of the interview were living in
Mexico). The measurement of return migration focuses on three retrospective
questions traditionally used in Mexico for census gathering (i.e., place of birth,
length of current and previous residency, and the place of habitual residency over
the past five years). The measurement of labor migration also utilizes retrospective
questions to ascertain if a migrant had been a worker or looking for work in the
United States and the time period (month and year) of the last movement. As with
other similar procedure, this one has several shortcomings: (1) third persons respond
for the emigrants, in which case the information is not very precise: (2) the
household does not necessarily exist with the same configuration and in the same
geographic location during the reference period; and (3) it is impossible to detect
emigration of complete families or of people who live alone, since there is no
reporting on these people. the survey thus generates an underestimate of the
magnitude of migration.
Despite these limitations, the data from the survey are valuable and indicate
that of the 85.164 million residents of Mexico in 1992,1.572 million were return
migrants and 2.28 million were previously labor migrants in the United States.
These figures cannot be added together because the two types of migrants are not
necessarily mutually exclusive. In fact, about 1.28 million people are members of
both groups, who simultaneously lived and worked in the United States; about 1
million people were “labor migrants”—individuals who do not consider their stays
in the United States to be for habitual residence in that country but rather for labor
reasons; and about 290,000 migrants did not work in North America during the
61
Table 19
Mexican-born Population Living in Mexico in 1992 by Living and Work
Experience in the U.S.
Worked in the U.S.?
Living experience in the U.S.
Total
Lived in
the U.S.?
Yes: Return Migrant
No: Not Return Migrants
Yes:
Labor
Migrants
to the U.S.
No:
Not Labor
Migrants
to the U.S.
85,164,449
2,283,815
82,880,634
1,572,192
1,282,469
289,723
83,592,257
1,001,346
82,590,911
Total
Source: Estimates of the authors using data from ENADID, 1992
period that they lived there. Together, the three categories of identified migrants
(those that lived and worked in the United States, labor migrants who did not reside
in the United States and non-working return migrants) total 2.57 million people,
which constitutes the number of Mexican residents in 1992 who had migrated to
the United States (see Table 19).
If we classify the migrants from the three categories by year of entry to the
United States or by year of return to Mexico, the numbers increase over time.
This increase is systematic and reflects two results: a) an increasing migration in
recent years, and b) the collecting of information in such a way that for each
individual only the last movements to the north is recorded, meaning that the
verifiable quantities of people who actually migrated in previous periods is
understated. Therefore, of the 2.574 million migrants mentioned above, 391,000
(15.2 percent) entered the United States before 1970; 396,000 (15.4 percent) did
so between 1970 and 1979; 603,000 (23.4 percent) between 1980 and 1987; and
1.098 million (42.7 percent) between 1988 and 1992. The rest fall under no specific
date of entry to the United States. Of those returning to Mexico, 349,000 (13.6
percent) did so before 1970; 331,000 (12.9 percent) did so between 1970 and
1979; 587,000 (22.8 percent) between 1980 and 1987; and 1.22 million (47.4
percent) between 1988 and 1992. The rest do not fall under any specific date of
return to Mexico. Table 20 shows the breakdown of the 1.22 million migrants that
returned to Mexico between 1988 and 1992 by year of return for each one of the
3 categories mentioned.
62
Table 20
Mexican-born Population Living in Mexico in 1992 that Lived and/or
Worked in the United States and Went Back to Mexico between
1988-92, by Year of Return from the United States
Work and/or
Residence Status
in the U.S.
Year of return to México
Total
1988
1989
1990
1991
105,074
162,966
201,524
279,143
471,368 1,220,075
Worked and lived
in the U.S.**
70,702
102,934
146,433
201,981
264,135
786,185
Worked but not
lived in the U.S.**
19,597
31,707
31,559
37,042
145,225
265,130
worked in the U.S.*** 14,775
28,325
23,532
40,120
62,008
168,760
Total
1992*
Lived but not
Source: Estimates of the authors using data from ENADID, 1992
*Labor migrants for 1992 include 47,767 persons that at the time of the interview where
working in the U.S. as well as 65,205 labor migrants that commute to work daily to the U.S.
*These figures refer to the year of return to Mexico after working in the U.S.
**These figures refer to the year of return to Mexico after living in the U.S.
For each reference or survey period there are differing groups of migrants who
enter or leave the United States. These differences are due to varying periods of
residency in North America. For example, we can estimate that between 1988 and
1992, a total of 1.098 million people entered the United States (an annual average of
220,000) and 1.220 million people returned to Mexico (an annual average of 244,000
people). Of these two figures respec tively, 707,000 and 786,000 fall under the category “lived and worked” in the United States, with an annual average of 141,000 and
157,000, respectively; 250,000 and 265,000 are those that “worked but did not live”
in the United States, with an annual mean of 50,000 and 53,000; and 140,000 and
169,000 are those who “lived but did not work” in North America, with an annual
average of 28,000 and 34,000. The difference between outgoing and return flows is
explained by differing periods of U.S. residency. Those who traveled to and returned
from the United States during the 1988-1992 interval include people who left the
United States in the reference period but had entered the country earlier.
The ENADID results also portray some demographic and socioeconomic characteristics of the migrants. Those who returned to North America between 1988
63
and 1992 (1.22 million) can be differentiated by the three migratory categories
above, showing that: the labor migrants (the “pure” ones and those who “worked
and lived” in the United States) are predominantly men (more than 80 percent). In
contrast, women represent the majority (60 percent) of the migrants who did not
work, indicating their greater role as companions; the labor migrants were basically young adults (more than 65 percent of those observed were between the ages
of 20 and 39), while those that did not work in the United States are in large part
adolescents and children (about 60 percent are less than 20 years of age); the labor
migrants are predominantly heads of families (about 60 percent), while in the majority of cases the spouses and children of the migrants did not work; of the “pure
labor migrants” and those who did not work, more than 50 percent were living in
the traditional zone of emigration (west central Mexico) during the time of the
interview, close to 25 percent were in the northern states, and between 15 and 20
percent were in the central region. Those migrants that worked but did not live in
the United States were interviewed primarily in the northern region (53 percent),
the traditional zone (24 percent) and the central area (20 percent). In all categories,
there was little participation from those residing in the southeast (between 1.5 percent and 3 percent).
The ENADID results also provide a basis for determining how many people
left Mexico to reside in the United States. Interviewees were asked if one or more
members of a household went to live in the United States in a specific period of
reference. Once identified, emigrants were questioned about their characteristics
(age, gender, family relations, date of emigration, current place of residency). The
question on “current place of residency” identifies emigrants who stay out of the
country as well as those who are return migrants. Return migrants were questioned
about their date of return. As with other similar procedures, this one had limitations: a) it relies on third person responses for the emigrants, in which case the
information may not be accurate; b) the household did not necessarily exist with
the same configuration and in the same geographic location during the reference
period; and c) it is not possible to identify emigration of complete families in transit or people living alone but in transit, since no one was at home to be interviewed.
In all, these limitations generate an underestimate of the magnitude of permanent
emigration. Nevertheless, the data thus established provide a pool of knowledge,
offering valuable information about the phenomenon. For example, the major results were:
• 1.823 million people left Mexico for the United States between January 1988 and November 1992, of whom 972,000 continued to live in
North America at the time of the interview (permanent emigrants) and
851,000 returned to Mexico after living in the United States (return
immigrants).
64
• Table 21 shows the breakdown of these migrants by the year of departure
to or return from the U.S. We can see that emigration appears to increase
over time: 226,000 left in 1988 (130,000 lived in Mexico and 96,000
still resided in the United States), 310,000 in 1989 (177,000 and 133,000,
respectively), 354,000 in 1990 (201,000 and 153,000), 351,000 in 1991
(186,000 and 165,000) and 581,000 in 1992 (156,000 and 425,000).
This could be due to various combinations of four circumstances: a) a
possible real increase in emigration to the United States; b) a reduction
in the permanent return emigrants in later years (there is a tendency to
remain indefinitely in the United States for about 40 percent of migrants,
but the percentage of those only remaining rises after at least three years);
c) the existence of a repetitious movement to the United States, which
diminishes the number of people from previous years because the single
migrants are placed in the most recent migration; and d) the greater
impact of questions about more recent events.
• With the goal of minimizing the distorting effect of the period of residency in the United States and to have a better approximation of the
magnitude of the phenomenon, we obtained the annual averages of the
years 1988-1992. These figures indicated that in the 1988-1992 reference period, an annual average of 365,000 people traveled to the United
States and established residency, of which 195,000 still lived in that
Table 21
Mexican-born population that went to live in the United States
between January 1988 and November 1992, by year of migration
and year of return to Mexico
Year
Migrated
Went back to live in Mexico
Total
U.S.
Live in the
Year of return to México
United
Total
1988
1989
1990
1991
1992
States
16,158
6,738
96,189
225,849
1988
129,660
41,708
40,603
24,453
1989
177,507
–
65,002
58,158
42,978
11,369
132,579
310,086
1990
201,158
–
–
82,911
89,672
28,575
153,108
354,266
1991
186,600
–
–
–
93,660
92,940
164,978
351,578
1992
155,797
–
–
–
–
155,797
425,323
581,120
Total
850,722
41,708 105,605 165,522
242,468
295,419
972,177 1,822,899
Source: Estimates of the authors using data from ENADID, 1992
65
country at the time the survey was carried out and 170,000 had already
returned to Mexico. This latter figure, although smaller, is similar to
the average mean return migration previously estimated for the same
period under questioning about place of birth and place of previous
residency (that is to say, 191,000 people, excluding “pure labor migrants”).
• The distribution of permanent emigrants and return immigrants underscores a well-known profile: a larger number of men, a structure marked
by youthful age (concentrated in the first years of economic activity), a
higher proportion of heads of households among the return migrants
and of children among the permanent emigrants; and, in general, a distribution by place of origin in Mexico that is similar to that previously
described.
The Migration Survey for the
Northern Mexican Border
The Migration Survey for the Northern Mexican Border is a continuing method
of generating data using procedures for quantifying mobile populations. In this
sense, the migrants are observed while they are traveling to work in the United
States or during their return to Mexico. When they arrive at Mexican border towns
and they gather in specific places in those cities, as for example bus or railroad
stations, airports or customs check points, it is then possible to select places for the
enumeration, sampling and interviews (Corona 1997; Santibañez 1997).
A first phase of this survey began March 28, 1993 and ended on March 27,
1994. The second phase spanned all of 1995. It conceptualized labor migrants as
units of movement observed at certain times and places in their migratory cycles
and identifies various target populations. The survey contributes useful information
that helps to answer the following questions: What is the magnitude of the flow
of Mexican labor to the United States in a specific reference period and how does
it vary in each phase of the survey? Has the labor flow increased, decreased, or
remained constant in the two phases of the survey? Which are the observed changes
in the composition of the flow that could be relevant to explaining the observed
changes in the magnitude of the flow? What proportion of the labor flow is
documented labor and what proportion is undocumented? How have these two
components of the flow evolved between the two survey phases or references
periods? What is the net outmigration when we compare outward flow to that of
the return flow in each phase? How has the net outmigration changed between the
two survey phases or between the two reference periods? What does this
outmigration signify?
66
In answer to these questions, we present some results based on the Northern
Border Survey. We examine first the magnitude and characteristics of the outward
flow (south-north flow) and then the return flow (north-south) flow. The available
data reveals that between the two phases, the flow toward the United States was
considerably reduced, rising to approximately 792,000 people in Phase One and
dropping to nearly 543,000 in Phase Two. If we analyze the data from the Northern
Border Survey just for the years 1993 and 1995, we obtain a similar conclusion.
The reduction in flow does not have a single interpretation. To identify the
significance of our results, we must consider that migrants must have in common
two basic conditions in order to be counted as part of the same flow: a) they must
reside in Mexico; b) and they must be headed toward the United States to work
or look for work. A member of the labor flow to the United States can be considered
the same whether he or she does not return to Mexico and “settles” in the United
States or whether he or she stops traveling periodically to that country to work or
look for work.
With these observations in mind, the previously mentioned trends can be interpreted in three different ways. First, the observed decrease in the magnitude of
the labor flow to the United States could be due to a reduction in the number of
people who form the group from Mexico. Among other factors, this would be associated with a) the difficulties (real or perceived) of entering the United States as an
undocumented migrant; b) the difficulties (real or perceived) of encountering employment there; and c) an increase in the direct or relative costs of movement from
the Mexican interior to the United States, which could be from loss of buying
power among potential migrants and from the devaluation of the peso relative to
the dollar. Second, the reduction in the magnitude of the labor flow to the United
States also could be attributed to large outmigration during previous reference periods. These migrants may have established residency in the United States or prolonged their stay, a fact that itself can be associated with, a) the difficulties (real or
perceived) of finding adequate remunerative employment in the migratory zone of
origin during a profound economic crisis; b) the strengthening of the role played
by the social and family networks in the United States; and c) the growing obstacles to leaving and returning to the neighboring country because of restrictive
immigration measures, particularly the strengthening of the U.S. Border Patrol.
Third, the trend could be a combination of the two previously mentioned possibilities. Specific weights for each factor would have to be determined in the future.
We questioned whether the Migration Survey for the Northern Mexican Border
contained sufficient data for testing our hypotheses. Our idea was that identifying
eventual changes in the internal composition of the labor current directed at the
United States would shed light not only on the characteristics of those who enter
or stay within the labor flow, but also those who leave it between phases. With
67
this idea in mind, we examined socioeconomic, demographic and family
characteristics of labor migrants, attempting to identify the most relevant changes
occurring between research phases or reference periods, the available data showed
among other things, that:
• the labor flow continues to be predominantly masculine;
• the migratory flow consists primarily of young people and adults of
economically active ages
• the members of the labor flow in general worked in Mexico before initiating their trips to the United States, although the relative weight of
those who lacked jobs increased in the recent period;
• most labor migrants come from the urban zones of the country (15,000
inhabitants or more), although in recent years the number of migrants
from rural areas has increased;
• the labor flow continues to originate predominantly in the federal entities that make up the traditional emigration zone (their relative weight
increased in the recent period), the numbers coming from northern, central and southern Mexico had decreased significantly.
• the state of California is the principal destination for labor migrants,
which also was characteristic of the earlier reference period;
• the number of labor migrants who intend to stay in the United States for
more than six months is increasing and the number who want to stay for
shorter periods is decreasing.
• the flow contains people who generally live alone or in other cases are
accompanied by people—family or non-family members—of 12 years
of age or more;
• the majority of labor migrants go to the United States regularly, although
in the most recent survey period this tendency lost relative weight in the
flow;
• the migratory flow consists of many workers who generally did not
have documents to enter or work in the United States, a characteristic of
labor flows in earlier periods;
• first-time migratory workers increasingly lack documents for entering
or working in the United States;
• workers who habitually travel to the United States for work increasingly lack entry or work documents as well.
68
• Summarizing, the flow of workers towards the United States not only
decreased in size, but there where also important changes in its characteristics. Some of these changes are very likely the result of migrants
with specific characteristics dropping out of the flow (e.g., those with
migratory experience in the United States, or those authorized to work).
In the case of the return flow from the United States (north-south) we observed that an important decline in absolute values, from more than 624,000 to
433,000 between Phases 1 and 2. This data is similar to data for the last three
quarters of 1993 and 1995, (518,000 migrants for 1993 down to 296,000 migrants
for 1995).
The demographic and socioeconomic characteristics of the return migrants
are generally similar to those of people in the south-north flow. In addition to
the already mentioned reduction in the magnitude of the return flow, we noted
that:
• the flow is formed primarily by men, although in recent years the relative weight of female participation has increased;
• first-time members of the return flow are concentrated within the economically active ages (between 12 and 34 years), but important changes
were detected in the age distribution between reference periods;
• as reflective of what took place in their outbound voyage, the return
flow is composed of people that generally undertake the trip alone or
are accompanied on their return trip by people—family or non-family
members—of 12 or more years of age;
• the majority of labor migrants stated that on their most trips to the United
States that they had entry documents, although the relative weight of
those individuals who did not have them grew. As a result, the flow has
a more balanced participation between the two groups;
• labor migrants with work documents on their most recent trip to the
United States were roughly equal to those without them in the earlier
survey period. In the most recent survey period, the number without
work documents dominated the flow;
• about 85 percent of first-time return migrants do not have work documents;
• about 87 percent of labor migrants did not need the services of a pollero
or coyote to enter the United States on their most recent trip; this is a
significant change from earlier periods;
69
• about 70 percent of return migrants had been to the United States only
once or twice before. This is consistent with trends from earlier periods;
• as with the south-north flow, many return migrants lack U.S. entry or
work documents and the number of first-time migrants without them is
increasing;
• but still, the majority of migrants with previous U.S. migratory experience had entry or work documents, although the relative weight of those
without documents has grown significantly.
• the majority of the return migrants are from urban areas of Mexico;
• the migrants who come from the states of traditional emigration constitute the largest portion of the return flow although their relative weight
has declined in recent years;
• California has been displaced in recent years by Texas as the primary
state of residence for migrants to the United States, and is identified as
such by a growing proportion of migrants;
• the main portion of the return migrants worked in Mexico before undertaking their most recent trip to the United States, but recently the relative weight of this group has diminished significantly;
• the largest part of the return flow did work during their most recent stay
in the United States (about eight out of every 10), although a slight
reduction is estimated for the relative participation of this group;
• a large number of return migrants sent monetary remittances to Mexico,
although the relative weight of this group has diminished enough to no
longer represent the majority in the observation period;
• the migrants declared as their principal reason for returning to Mexico,
in order of importance: 1) to visit their families; 2) to rejoin the work
force in their respective places of habitual residency; 3) because they
had not worked in the United States; 4) because they had been apprehended by the U.S. Border Patrol. In recent years, the number of migrants who said they were apprehended has increased significantly and
those returning to visit families.
Available information indicates similar demographic and socioeconomic characteristics had decreased between the groups of return labor migrants and departing labor migrants. But one difference in the most recent flow is the decline of the
relative weight of the return migrants who originated in the traditional states of
emigration and those from rural areas (in contrast to the growing participation of
70
those who come from the northern region and the urban zones of the country). This
suggests lengthier stays in the United States among those migrants originally from
the north or the urban zones. And they may be supported by more solid social
networks and family linkages between origin and destination.
The difference between the figures of the two directions of the flow represent
the net migration, which may produce either a gain or a loss of population, which
is due almost exclusively in the labor migration flow during the period of reference. In the first round the net balance was negative and reached some 167 thousand people, whereas in the second round it was also negative and reached 109
thousand, which is 65 percent of the balance of the earlier round.
Indirect Measurement Efforts
Because direct measurement of migration to the United States is so difficult,
researchers have largely relied on indirect measurement and have developed a number of methodologies for estimating migratory flows. Indirect measurement procedures have been refined over time with new types of statistical databases and with
new data on specific aspects of migration. Nevertheless, the accuracy of the measures still depends on certain assumptions about an “invisible statistic”—the migrant population—that cannot be verified through available information sources.
One way to confront this limitation is to make changes in the theoretical assumptions used and then analyze the variation in research outcomes under the modified
assumptions. Even though the procedures for indirect measurement have little to
offer in terms of definitive or conclusive results, the measurements have considerably reduced the margin of uncertainty about the magnitude of the migration phenomenon. (Castro 1990; CONAPO, 1992a, 1992b, 1995a, 1995b; Corona, 1991,
1994, 1995; Partida, 1990). The estimates from indirect measures that have been
based on data from Mexico (see Table 22):
• indicate that the loss of Mexican population from international migration has been systematic since 1960;
• establish limits to the estimates of permanent Mexican migration to the
United States between 260,000 and 290,000 in the decade of 19601970; between 1.2 million and 1.55 million during the decade of 19701980; and between 2.1 million and 2.6 million in the decade 19801990. These figures indicate that the net annual flow has increased with
the passage of time, going from about 28,000 in the decade of 19601970, to close to 140,000 in the following decade and at 230,000 in the
decade 1980-1990.
• confirm that the estimated magnitude of the flow in the past decade is
71
Table 22
Estimates of net permanent migration from Mexico
to the United States, 1960-1990
Author
Decade
1960-70
1970-80
Corona 1991
1980-90
1975-80
1980-85
1985-90
1,069
1,232
1,214
1,385
1,500-3,000
CONAPO dec. 1992
Corona 1994
Half Decade
2,301
275
1,476
2,378
2,113
Corona 1995
286
1,533
2,444
287
1,366
2,307
Partida 1990
1,277
585
Castro 1990
1,215
563
CONAPO Aug. 1992
2,599
563
CONAPO March 1995
2,093
889
1,204
CONAPO Jul. 1995
2,108
899
1,209
considerable and that the effect of this flow on the dynamic of
demographic growth in the country is perceptible.
• The results of these indirect measures of the net migration flow between Mexico and the United States are very reasonable, they are consistent with the demographic changes of Mexico’s population and they
are in general agreement with the estimates carried out with United States
data sources.
With the idea of counting with an indirect measure of migration between Mexico
and the United States during the most recent period, (for the five years between 1990
and 1995), in research carried out for this report we used a residual procedure (that
is derived from the use of a balancing equation) with information from the Population
and Housing Count of 1995 (published at the end of April 1996 and referring exclusively to the total inhabitants of Mexico classified by sex and federal entity) and data
from the Eleventh General Census of 1990. The main results obtained from this
72
Table 23
Estimates of the Mexico’s Net International Migration Flow
between 1990 and 1995 by State of Residence
State of Residence1
Total
Annual average
-1,387,481
-277,496
North
-338,584
-67,717
Traditional
-664,824
-132,965
Central
-383,792
-76,785
-281
-56
Total
Southeast
1
State of Residence:
North: Baja California, Baja California Sur, Coahuila, Chihuahua, Nuevo León,
Sinalóa, Sonora and Tamaulipas.
Traditional: Aguascalientes, Colima, Durango, Guanajuato, Jalisco, Michoacán,
Nayarit, San Luis Potosí and Zacatecas.
Central: Distrito Federal, Guerrero, Hidalgo, México, Morelos, Oaxaca, Puebla,
Qurétaro and Tlaxcala.
Southeast: Campeche, Chiapas, Quintana Roo, Tabasco, Veracruz and Yucatán.
procedure (for the national totals) are the following: For 1990-1995 net outmigration
was 1.387 million people, with an almost equal participation by sex (694,000 men
and 693,000 women) and the net count gave a distribution by groups of entities
located inside the known migratory pattern (47.9 percent in the traditionally highest
zone of migration; 24.4 percent in the northern states and 27.7 percent in the central
entities). The figure of 1.39 million people is an estimate of net outmigration during
the five-year period between 1990-1995, which is equivalent to an annual average of
277,000 people ( see Table 23). This estimate (1) is substantially higher that that
observed during the decade 1980-1990; (2) agrees with that developed independently
by the Mexican Population Council (CONAPO); and (3) is relatively close to the
figure of 316,000 estimated with U.S. data sources in research conducted for this
report. It also should be noted that this estimate is also higher than that directly
derived from ENADID, which in turn suggest that an important number of Mexican
migrants lived alone in their places of origin before leaving to the U.S. or left the
country with all members of their households.
Other results obtained from this procedure (for the national totals) are the
following:
73
• If the natural growth (and the interstate migration) of the five-year period
is correct and if the states of the southeast do not have significant
migration to the United States, then the positive outmigration
encountered for these six entities (35,000 women and 70,000 men)
constitutes a better measurement in the enumeration of the 1995 count
than in the enumeration of the 1990 census. The census population,
corrected for undercounts stemming from the 1990 census (0.52 percent
for the total, 0.70 percent for men and 0.34 percent for women), was
used to obtain an estimate of net outmigration of 1.166 million emigrants,
with a balanced participation of men and women (576,000 male
emigrants and 590,000 female emigrants) and a distribution by groups
of origin (54.2 percent coming from the states with traditionally high
migration; 25.3 percent from northern states and 20.5 percent from
entities located in the center of the country), which is consistent as much
with the migratory trend up to 1990 as with the data from the survey
carried out for the period 1990-1995.
• The second estimate was carried out using the same operations and considerations from the previous calculation, but with some modification.
Instead of calculating the population by gender and entity in 1995 as a
sum of the residents in 1990 plus the natural increase (and increase due
to internal migration), the population is determined as a product of the
residents in 1990 by a factor that accounts for the growth in declining
international migration. This was the basis for establishing a percentage
of undercoverage from the 1990 census that was almost double the figure
used in the previous estimate (0.92 percent for the total, 1.22 percent for
men and 0.63 percent for women). With this method, the net outmigration
rose to 1.387 million people, with an almost equal participation by gender (694,000 men and 693,000 women) and the new count gave a distribution by groups of entities located inside the known migratory pattern
(47.9 percent in the traditionally highest zone of migration; 24.4 percent
in the northern states and 27.7 percent in the central entities).
The two previous estimates did not yield such disparate results, in spite of
the utilization of different assumptions about the undercoverage of the 1990 census.
The differences rose to 19 percent of the total, 20.5 percent for men and 17.5
percent for women. Nevertheless, if the differences between one calculation and
the other with respect to the distribution of outmigration by groups of entities are
accurate, the differences are not tremendous for the northern states and for the
states of traditionally high migration (14.8 percent and 5.1 percent, respectively),
but the difference is tremendous for the central entities (60.7 percent). This marked
74
contrast between the results of the two estimates shows the need to carry out a
more detailed analysis of the same, revising the internal coherency, in order to
choose one of these estimates as the definitive product of this residual
methodological application. The figure of 1.387 million people corresponds to
our estimate of net outmigration during the five-year period between 1990-1995,
which is equivalent to an annual average of 277,000 people. This quantity, slightly
higher than that observed during the decade 1980-1990, results in a negative annual
international migration rate of 0.31 percent.
Immigration to Mexico
Immigration to Mexico is not very large. Table 24 shows the number of foreign
immigrants that lived in Mexico in 1970, 1980, 1990 and 1992 by sex and country
of birth. During the decades of the 1970s and 1980s, annual average increases of
7,000 immigrants were reported. The 1990 Census data indicated that by 1990, a
total of 340,00 foreigners resided in Mexico, which represents scarcely 0.42 percent
of the country’s inhabitants. Data from the National Survey of the Demographic
Dynamic reinforced this estimate, but also indicated that in recent years,
immigration to Mexico has intensified substantially (between 80,000 and 100,000
in the period between March 1990 and November 1992, inclusive). The
demographic and socioeconomic characteristics of migration to Mexico are:
• a similar proportion of men and women immigrated, and did not show
significant variation by place of origin or by period of entry to Mexico;
• the United States is, by far, the principal country of origin for the immigrants (more than 50 percent of the immigrants are natives of that country), followed by natives of Central and South America, and after them,
in lesser numbers, natives of Europe, Asia and Africa;
• the composition by age differs by place of origin. The natives of the
United States exhibit a peculiar distribution: more than 40 percent are
less than 10 years of age and almost 30 percent are children or adolescents between 10 and 19 years of age. This fact seems to be associated
with return migration of Mexicans—who bring with them children born
in the United States. The apparent intensity of immigration observed
between 1990 and 1992 appears to explain, in large measure, the increased numbers of children. In contrast, the immigrants of non-American countries display a structural aging and the Central and South Americans conform to a youthful age profile.
• 10 geographic entities in Mexico attract about 80 percent of the
immigrants: Baja California, Chihuahua, Nuevo León and Tamaulipas
75
Table 24
Foreign-born Residents in Mexico, by Sex and Country of Birth, 1972-1992
Sex and
Country of Birth
1970
Census
1980
Census
1990 Census
Enumeration One percent
1992
ENADID
191.2
268.9
340.8
349.3
463.4
Male
Female
97.3
93.9
134.2
134.7
171.8
169.0
168.2
181.1
235.7
227.7
United States
Rest of Americas
Rest of the World
Not Specified
97.2
31.5
62.5
–
157.1
45.1
66.2
0.5
194.6
90.7
54.9
0.6
191.5
86.7
56.8
14.3
278.7
143.5
41.2
–
Percentage Total
100.0
100.0
100.0
100.0
100.0
Male
Female
50.9
49.1
49.9
50.1
50.4
49.6
48.2
51.8
50.9
49.1
United States
Rest of Americas
Rest of the World
Not Specified
50.8
16.5
32.7
–
58.4
16.8
24.6
0.2
57.1
26.6
16.1
0.2
54.8
24.8
16.3
4.1
60.1
31.0
8.9
–
Immigration rate
(per 100)*
0.4
0.4
0.42
0.43
0.54
Absolute numbers
(in thousands)
Total
Source: Census of Population and Housing, 1970, 1980 and 1990
(Data from the total enumeration and the one percent sample) and ENADID, 1992
* Total foreign born divided by total resident population in Mexico (per 100)
in the northern border region; Guanajuato, Jalisco and Michoacán in
the plateau region of northern Mexico and the west; the Federal District
and the state of Mexico in Central Mexico; and Chiapas in the southeast.
The distribution of the immigrants in the 10 areas varies by country of
origin. The natives of the United States reside basically in the north and
the west, also zones of outmigration to North America (the later reinforces
the hypothesis that part of the immigration coming from the United
76
States is linked to migration from Mexico to the United States). In the
Valley of Mexico, more than 60 percent of immigrants were born on the
American continent. About 40 percent of the immigrants living in
Chiapas come from the south, especially from Central America.
The flow of immigrants from Central America have received special attention
in the past several years because of their growing importance and apparent regional impact on Mexico’s southern border. The available research on this issue
has progressively characterized the typology of these flows, pointing to the following: a) the seasonal agricultural workers; b) the Guatemalan refugees; and c)
the undocumented transmigrants.
• the flow of agricultural workers is directed principally at Chiapas. Measuring these workers has been difficult because a significant number of
them (the proportion cannot be determined) habitually move without
documents. Past estimates, coming generally from migration officials,
are derived more from individual observation and practical experience
than from procedures that rely on analytical and empirical bases. More
recently, the efforts of migration authorities to standardize this flow has
generated some additional data, but not enough to estimate the flow
reliably. The most recent migration records identify between 50,000
and 75,000 documented entries annually into Mexico (although a single
entry can include several people). This figure is derived from an inferior threshold, however, because it does not include undocumented entries, which at the present time are impossible to quantify.
• the Guatemalan refugee populations, which is encamped at Chiapas,
Campeche and Quintana Roo, rose at the beginning of 1996 to about
32,000 people. But it is believed that an undetermined additional number of refugees exist but are not known as such because they can be
found scattered throughout the territory and because they arrived in
Mexico during the 1980s in conditions very similar to those of refugees
established in the camps.
• the undocumented transmigrants are those people who have penetrated
the national territory with the idea of moving to a third country. As with
the migration to the United States, the surreptitious nature of this
movements obscures the ability to measure them. We can rely on only
those figures that match the number of deportations and expulsions
carried out by migration authorities. These figures only give an indirect
idea of the significance of this movement. The expulsions have been
constantly rising and demonstrate two points of inflection: one is in
1980, when the expulsions exceeded 10,000 actions, and the second is
77
in 1990, when the figure surpassed 100,000 annual actions. Almost all
of the expulsions carried out in the past several years have been
systematically against migrants coming from Guatemala, El Salvador
and Honduras.
Summary of Results from Estimating
Procedures and Update to 1996
As of 1980, stock and flow estimates of the unauthorized migrant population
tended to be unreliable due in part to lack of methodologies for correcting for
biases in the available data sources. For instance, better methods had to be developed in order to make more valid estimates of in-flow on the basis of INS apprehensions and nonimmigrant entrance/exit forms. Also, early analytic estimates tended
to be inconsistent in their assumptions, methodologies, and consequently, in the
populations they described. Hence, the various estimates were difficult to compare
and evaluate (Bos, 1984). Finally, reviewers (Siegel, et al., 1980; Hill, 1985b) found
that most early analytic estimates of stock and flow were sensitive to their underlying assumptions. More complete data about the foreign born and the unauthorized migrant population had to be obtained in order to better support underlying
assumptions, such as those made about undercount (Goldberg, 1974; Heer, 1979)
and death rates (Robinson, 1980). As a result of these and other problems, Siegel
and his co-authors concluded in 1980 that there were “currently no reliable estimates of the number of unauthorized residents in the country or of the net volume
of unauthorized immigration to the United States in any past recent period” (1980).
Nevertheless, they conceded that the analytic studies supported the view that by
the end of the 1970s, 2.5 million to 5 million unauthorized migrants and 1.5 million to 2.5 million unauthorized Mexican migrants resided in the United States.
The residual studies conducted during the 1980s obtained results at the beginning
of the 1980s that tended toward the lower end of this range, subject of course to
considerable uncertainty about the fraction of the unauthorized Mexican migrant
population not enumerated in the official U.S. Censuses and surveys on which they
were based, as discussed at length above. The results of these studies also showed
the effects of IRCA’s legalization programs, which removed substantial numbers
of undocumented migrants from the estimates of stock. They also revealed that the
unauthorized migrant population (both overall and from Mexico) continued to grow
annually during the 1980s, diminished in total numbers only by the legalization
programs of IRCA.
Several broad classes of factors affect the significance and meaning of these
(and in fact any) estimates. One, of course, is their accuracy. To what degree can
we be confident that the figures reflect the sizes of the populations they are intended
78
to represent? While uncertainties remain (as noted in discussions above), there is
little question that the results of research on the magnitude of stocks and flows
during the 1980s have narrowed considerably the range of plausible estimates.
However, because of data gaps (e.g., the deletion of I-53 registration system,
inadequate information on emigration, and little empirical data on the undercount
of the unauthorized population), estimates during the 1990s that rely on residual
approaches may be subject to increasing uncertainty, and thus perhaps are
increasingly likely to generate broad ranges of estimates (Woodrow-Lafield, 1996).
Another factor that effects the significance of estimates is the context in which
they occur. Estimates are most appropriately viewed not in isolation, but in relation to other kinds of changes, including population changes. We discussed above
the policy significance of possibly shifting proportions of EWIs and visa overstayers.
More broadly, it is of interest to examine how the estimates of unauthorized Mexican migration compare to population size generally in both the United States and
Mexico. The estimated enumerated unauthorized Mexican population (1.131 million) in 1980 represented about 51 percent of the total Mexican-born population in
the United States, 8 percent of the U.S. foreign-born population, 12.9 percent of
the total Mexican-origin population, 0.4 percent of the total U.S. population, and
1.7 percent of the total Mexican population.
What evidence is there about the size of the unauthorized Mexican migrant
population during the 1990s? Estimates of Mexican unauthorized migrants should
readily square with evidence about (1) the overall size of the Mexican-born
population in the United States, (2) estimated rates of underenumeration in the
legal unauthorized populations, and (3) estimates of the size of the legal Mexicanborn population. A 1996 figure for unauthorized Mexican migrant stock may be
constructed by starting with the overall size of the enumerated Mexican-born
population from the March 1996 CPS of 6.68 million. Based on the evidence in
Hogan and Robinson (1993) and Van Hook and Bean (1997) about undercount
rates, we set plausible underenumeration rates for the legal and unauthorized
Mexican populations at 4 and 12 percent respectively. Consistent with the evidence
that about 700,000 SAWs were in the United States in the 1990s, we also adopt
a mid-range estimate of 4.8 million legal Mexican immigrants (Woodrow-Lafield,
1997). Given these values, the enumerated number of legal immigrants is estimated
as 4,608 million (4.8 x 0.96 = 4.608) and the number of unauthorized immigrants
as 2.35 million (6.679 - [4.8 x 0.96]/0.88 = the number of unauthorized migrants
= 2.35). Placing a 90 percent confidence interval around the overall total of 7.15
million Mexican-born persons in the United States in 1996 (obtained by adjusting
for undercount) adds and subtracts about 150,000 from each side of this value,
giving and estimated range of 7 milliion to 7.3 million total Mexican-born persons
in the United States. In 1996, then, a figure of 2.35 million unauthorized Mexican-
79
born migrants would represent 37.8 percent of the U.S. Mexican-born population,
10.2 percent of the U.S. foreign-born population, 11.6 percent of the Mexicanorigin population, 0.8 percent of the total U.S. population, and 2.3 percent of the
Mexican population.
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89