Are There Race and Ethnicity-based Salary Gaps in Engineering?
Bhavya Lal and Ken Carlson1
Abt Associates Inc.
This issue brief examines the salary differences by race- and ethnicity in engineering, a profession in which
underrepresented minorities2 held 6 percent of the jobs in 19973. The authors computed the magnitude of the
salary gaps among the five primary racial and ethnic groups and using statistical methods explored various
potential explanations for the salary gap in this occupation. The analysis showed that the salary gap is primarily
explained by two factors: underrepresented minority engineers, on average, have fewer years of experience
since their first baccalaureate degree than whites and Asians, and fewer of them have degrees beyond the
baccalaureate. Taking into account these and other minor factors, the salary difference disappears completely
for Hispanic and Native American engineers, and is reduced to 2.5% for black engineers.
Using 1997 survey data from the National Science Foundation, the study focused on 1.6 million U.S. residents
up to age 75 who were employed full-time as engineers4. Within this population, the median salary for underrepresented minorities was about 10% less than the median salary for non-Hispanic whites. Asians, on average,
earned the same as or more than whites.
The authors first identified the major determinants of engineering salaries, and then explored whether the racial
and ethnic groups differed on these factors. Median regression analysis was used to determine whether these
factors, alone or together, could explain the salary differences. Factors used in the regression as independent
variables included: engineering specialty, employment sector, earned engineering degrees, highest degree
attained, years of experience, gender, and main work activities (such as involvement in management, design,
production, research, development, computer applications, or teaching). This technique provides an estimate of
the size of the salary differences among groups of engineers who were identical on these measures, but different
in race or ethnicity.
Explaining the Salary Gap
In 1997, non-Hispanic white and Asian engineers earned a median annual salary of $60,000 (rounded to the
nearest thousand). Median salaries of black and Hispanic engineers were $52,000 and $55,000, respectively.
Few native Americans were represented among the engineers in the sample (two percent of minorities in the
engineering workforce are Native American), so estimates of their salaries are less precise; their salaries
resemble those of other underrepresented minorities at a median of $53,000.
An analysis of salary data shows that most of the salary gap among the racial/ethnic groups can be explained as
follows:
The authors are researchers at Abt Associates, Inc., Cambridge, MA. This study was supported by NSF’s Directorate for
Engineering, Division of Engineering Education and Centers.
2
The term “minorities” refers to the five primary racial and ethnic groups – non-Hispanic white, black, Hispanic, Asian,
and Native American. The term “under-represented” minorities refers to blacks, Hispanics and Native Americans.
3
These data were derived from SESTAT (Scientists and Engineers Statistical Data System), a comprehensive and
integrated system of information about the employment, educational, and demographic characteristics of scientists and
engineers in the United States. For more information, see the SESTAT Web page [http://sestat.nsf.gov].
4
Unlike other publications using SESTAT data, this study included computer software engineers as engineering
occupations. Not included are the engineering-related occupations of senior and mid-level technical manager and
engineering technologist. All engineers discussed in this brief have a baccalaureate or higher degree.
1
Figure 1: Relationship between years since first baccaluareate and median salary by US engineers
employed full-time by race/ethnicity: 1997
Note: Plots in Figure 1 are salaries of full-time engineers in 1997, who were US citizens or permanent residents.
The Figure shows regression estimates of the median salaries for racial/ethnic groups grouped by years since first
baccalaureate, no other variables were controlled. The figure was generated by applying median regression to the
reported salaries
Source: National Science Foundation, Division of Science Resources Studies,
SESTAT (Scientists and Engineers Statistical Data System), 1997
Black, Hispanic, and Native American engineers have, in general, fewer years of experience than
their white and Asian colleagues. For engineers in every ethnic group, the time elapsed from the year
of an individual’s first bachelor’s degree award used in this study as a proxy for years of work
experience is an important determinant of salary. Only one percent of all working engineers who
received baccalaureates before 1971 are black, and fewer than two percent are Hispanic. Among recent
graduates (those with baccalaureates conferred after 1990) four percent are black and five percent are
Hispanic. Thus engineers from underrepresented minority groups have less experience than other
engineers: white and Asian engineers average three more years of experience than Hispanic engineers
and four more years than black engineers.
Figure 1 shows the relationship between years since baccalaureate (a measure of experience) and
median salary.5 As predicted, salary levels increase with years of experience, and the gap between the
groups narrows considerably when controlled for years of experience. For black engineers, experience
5
The figure shows year-by year median salaries, smoothed by moving medians of 5 year intervals. (Tukey, John W.,
Exploratory Data Analysis, Addison-Wesley, Reading, MA, 1977.)
alone explains 60% of the salary gap, for Hispanic engineers 80%, and for Native Americans 75%.
Regression analysis shows that the gaps among ethnic groups are largest for early graduates, and
disappears entirely for those receiving degrees since 1992.
Black, Hispanic, and Native American engineers who received their baccalaureate in the same
year are significantly less likely than whites or Asians to have degrees beyond the baccalaureate.
In 1997, engineers with only baccalaureate degrees earned a median annual salary of $56,000, while
those with masters' degrees earned $65,000 and doctorates earned $73,000. Black engineers are less
likely than white, Hispanic, or Asian engineers to have post-baccalaureate degrees – only 20 percent of
black engineers have advanced degrees compared with 35 percent of non-Hispanic white engineers and
60 percent of Asians.
Lack of advanced degrees explains another 8% of the salary gap for blacks, 16% for Hispanics, and 4%
for Native Americans.
Other characteristics of engineers – their field of engineering, their sector of work, whether they had a degree in
engineering, and their main activities on the job -– all affect salary levels for engineers of all ethnicities6, but
account for an insignificant portion of the remaining salary gap. Together they explain 5% of the salary gap for
black engineers and 16% for Native Americans (the margin of error for Native Americans is high given their
small numbers). These other factors do not affect the gap for Hispanic engineers.
Conclusions
Experience, post-baccalaureate degrees, and the other factors identified explain approximately 75, 96 and 94
percent of the salary gap between the majority whites and blacks, Hispanics, and Native Americans,
respectively. The remaining unexplained gap is only slightly larger than the margin of error for the estimates on
which these analyses are based.
The analysis also revealed that even after controlling for all the factors mentioned, younger minority engineers,
i.e. those who left school most recently (during the 1990s) earn salaries identical to their non-minority
counterparts, while those who completed baccalaureates in the 1970s earned about $6,000 less than nonminority engineers with similar degree levels. Table 1 illustrates these differences. Data not shown in the table
indicate that the salary differences may be slowly disappearing: on average, each successive graduating class of
black engineers since 1970 has narrowed the gap by approximately $250.
Table 1: Salary differential of minorities with respect to
non-Hispanic white engineers
Years
Hispanic
Black
Asian
Native
since first baccalaureate
American
0
-800
0
2,000
-3,400
5
-2,000
0
2,000
-2,440
10
-1,000
-5,000
0
464
15
-1,000
-6,000
-1,000
-*
20
0
-4,000
-2,000
-*
25
0
-2,000
-3,000
-*
Note: Cells with * represent suppressed data
Source: National Science Foundation, Division of Science Resources Studies,
SESTAT (Scientists and Engineers Statistical Data System), 1997
6
People employed as engineers who have engineering degrees earn $3,000 more in median salary than those without
engineering degrees when other factors are controlled.