Methodology

The unauthorized immigrant estimates throughout this report are produced using a multistage method that first subtracts the estimated lawful foreign-born population from the total foreign-born population to derived estimates of the unauthorized immigrant population (for large states and the balance of the country, for adults and children and by region of birth). The residuals then are used as control totals for a probabilistic process that assigns legal status to individuals in the survey based on their age, region of birth, family relationships and other socio-demographic characteristics. Finally, the resulting estimates are adjusted to take into account persons omitted from the survey.

The main source of data for estimates from 2005 to 2014 is the U.S. Census Bureau’s American Community Survey, tabulated from the public-use file obtained from the Integrated Public-Use Microdata Series or IPUMS (Ruggles et al., 2015). Estimates for 1995 and 2000 use the bureau’s March supplements to the Current Population Survey. See Passel and Cohn 2016 for more detail.

The estimates included here supersede all previously published estimates of unauthorized immigrants, and may differ slightly from previously published estimates.

The labor force includes all people ages 16 and older who are working or looking for work. For the analyses of occupations and industries, we exclude people who did not report an occupation or industry. In our analysis, we also exclude people in the military or with a military occupation. These exclusions drop about 2% of the total labor force of roughly 161 million – 2.9 million are excluded from the occupation analyses and 3.4 million from the industry analyses. About 120,000 unauthorized immigrants, or 1.5% of those in the workforce, are excluded from this analysis because they do not report an occupation or industry; unauthorized immigrants are generally not eligible to be in the military or to hold military employment, so are not excluded for that reason. Unemployed people are only excluded if they do not report an occupation or industry, although most do report them.

Rounding of estimates

All estimates for immigrant populations, lawful and unauthorized, are presented as rounded numbers to avoid the appearance of unwarranted precision in the estimates. The rounding conventions for immigrant estimates, dependent somewhat on data sources, are:

Greater than 10,000,000 Nearest 100,000

1,000,000-10,000,000 Nearest 50,000

250,000-1,000,000 Nearest 25,000

100,000-250,000 Nearest 10,000

5,000-100,000 Nearest 5,000

<5,000 Shown as <5,000

State and national data for the total and U.S.-born populations are rounded to the nearest 10,000. Unrounded numbers are used for significance tests, for plotting charts and for computations of differences and percentages. Where differences are reported, they are computed from unrounded estimates and then rounded separately. Because each figure is rounded separately, the rounded estimates may not add to rounded totals. Similarly, percentages computed from rounded numbers may differ from the percentages shown in this report.

Industry and occupation category labels

The Census Bureau has three different levels of aggregation each for industry and occupation. At the highest level, there are 12 classifications for “major occupation” groups (11 for civilians, plus the armed forces). At the next level, there are 23 “detailed occupation” groups, but eight of them are identical to the “major” groups; the three major occupation groups for management, professional and service occupations are subdivided into 15 smaller, detailed groups. Finally, there are a large number of very specific occupation categories – almost 600 – which can be grouped into either the “detailed” or “major” groups. So, for example, the code for “Aerospace engineers” (1320) is part of the detailed category for “Architecture and engineering occupations” which, in turn, is part of the major category of “Professional and related occupations.”

For industries, the highest level has 14 “major industry” groups (13 for civilians and one for the armed forces). At the next level, there are 52 “detailed industry” groups. Unlike with occupations, only four of the “major” groups are identical to “detailed” groups. Finally, there are 273 very specific industry categories that can be grouped into either the “detailed” or “major” groups. So, for example, the industry called “Retail bakeries” (code 1190) is part of the detailed category for “Food manufacturing” which, in turn, is part of the major category of “Manufacturing.”

The analyses presented here use the “major” categories for both occupations and industries. Some data are presented for the very specific occupations and industries with the highest concentrations of unauthorized immigrants.

For ease of presentation, the full titles of many industry and occupation categories have been condensed from the Census Bureau’s terminology in some figures and text. If so, they are shortened as follows:

Agriculture, forestry, fishing, and hunting Agriculture

Mining no change

Construction no change

Manufacturing no change

Wholesale and retail trade Wholesale/retail

Transportation and utilities Transport/utilities

Information no change

Financial activities no change

Professional and business services Business services

Educational and health services Education/health

Leisure and hospitality Leisure/hospitality

Other services no change