Steven Camarota’s Methodology
for Assigning Illegal Immigration Status Probabilities
Center for Immigration Studies researcher, Steven Camarota employed the following
methodology for determining probability of legal and illegal immigrants under
examination within his research: Illegal Immigrants and HR 3200: Estimate of Potential
Costs to Taxpayers.”
Using data collected from the U.S. Census Bureau’s Current Population Survey (CPS),
survey respondents were determined to have legal or illegal immigrant standing based on
examination of the following factors: citizenship status, year of arrival in the United
States, age, country of birth, educational attainment, gender, receipt of welfare programs,
receipt of Social Security, veteran status, and marital status.
The researcher compared results of both the total number of illegal immigrants and the
characteristics of this population to other research estimates in the field of immigration
studies. Most notably, research conducted by the Department of Homeland
Security/legacy INS, the Urban Institute, and the Pew Hispanic Center was examined.
Probabilities were assigned to match closely with the commonly held estimates derived
by each of these non-partisan entities.
The distinguishing elements for probability assignment were selected due to researchbased assumptions regarding commonly defined characteristics of illegal immigrants in
the United States. An example of this kind of assumption is that illegal immigrants are
disproportionately young, male, unmarried, and have few years of education. Similar
assumptions were made for each of the ten probability criteria listed above. Probabilities
are assigned to these factors in order to determine the likelihood of legal or illegal status.
Those individuals with a cumulative probability of one or higher were assumed to be
illegal immigrants.
There were also instances identified in which researchers assumed there to be no
probability for illegal status, such as respondents who identified themselves as recipients
of Social Security payments or who were U.S. veterans.
For comparison purposes, the CPS illegal immigration status totals are based on an
analysis that uses administrative data to estimate the size and characteristics of the legal
immigrant population. These figures are then subtracted from the survey respondent
totals of foreign-born immigrants, to derive a residual number of respondents deemed to
be illegal immigrants.