This blog examines the impact of immigration on population growth from 1982 to 2017. We have done a similar analysis previously. This analysis is based entirely on the Census Bureau’s American Community Survey and the Current Population Survey Annual Social and Economic Supplements. We find that in 2017 there were 35.78 million legal and illegal immigrants living in the United States who arrived from 1982 to 2017. Further, these immigrants had 16.93 million U.S. -born children and grandchildren. In total, immigration added 52.7 million people to the U.S. population between 1982 and 2017, accounting for a little over 56 percent of population growth over this time period.
Methodology
Key Terms. In this analysis, we use the terms “immigrant” and “foreign-born” synonymously. Immigrants include all persons who are not U.S. citizens at birth — naturalized citizens, lawful permanent residents (green card holders), long-term temporary visitors (e.g. guestworkers and foreign students), and illegal immigrants. We also use the term second-generation Americans to describe those born in the United States to immigrant parents — their immigrant parents are the first generation.
Data Sources. There are several different ways to measure the impact of immigration on population growth retrospectively. In this blog, we use Census Bureau survey data. In particular, we rely on the 2017 American Community Survey (ACS) and the 1999 and 2017 Current Population Survey Annual Social and Economic Supplements (CPS ASEC). It is well established that Census Bureau surveys of this kind include both legal and illegal immigrants.
The ACS is one of the nation’s largest surveys and has become one of the most important sources of information on the nation’s foreign-born population. The CPS ASEC, henceforth referred to as just the CPS, is a smaller survey that also identifies the foreign-born. In addition to identifying immigrants, both the ACS and CPS also ask immigrants what year they came to the United States. We use the ACS to measure the number of immigrants living in the United States who entered in 1982 or later. In addition to identifying immigrants and their year of arrival, the CPS also asks each respondent the birthplace of their parents, allowing us to measure the number of children post-1982 immigrants had once in the United States.
Number of Post-1982 Immigrants. The ACS shows 36.04 million immigrants living in the United States who arrived in the country in 1982 or later. The Census Bureau’s population estimates used to measure population growth reflect the population on July 1 of each year. However, the ACS measures immigrant arrivals by calendar year. To align the arrival data with the July 1 date of the population estimates, we exclude half of the immigrants who indicated in the 2017 ACS that they arrived in 1982. This creates our estimate that 35.78 million immigrants arrived from July 1, 1982, to July 1, 2017. Of course, the total number of immigrants who arrived over this time period was higher, but some share died or left the country by 2017. As they are not in the country in 2017, they are not adding to the population.
U.S.-Born Children in 1999. To estimate the number of U.S.-born children of post-1982 immigrants, we first assume that children under age 18 live with their parents. This allows us to measure the number of second-generation Americans who have a parent who arrived in 1982 or later based on the year of entry of their parents. Of course, adult children typically do not live with their parents. To estimate the number of adults in 2017 with post-1982 immigrant parents, we use the 1999 CPS. The 1999 data shows that 50.7 percent of all second-generation children under age 18 with a foreign-born mother are the children of post-1982 immigrants. (We exclude those with only an immigrant father to avoid double counting.) As will become clear below, we use this percentage to estimate the number of second-generation adults in 2017 whose parent arrived in 1982 or later.
Second Generation Adults in 2017. By 2017, second-generation individuals born between 1982 and 1999 were adults, a large share of whom no longer live with their immigrant parents. However, based on the population shares in 1999, we assume that 50.7 percent of second-generation Americans born between 1982 and 1999 with an immigrant mother were the children of a post-1982 immigrant in 2017. This comes to 4.44 million. The remainder of U.S.-born second-generation Americans in this age group were born to parents who arrived prior to 1982.
Second Generation Children in 2017. Using the 2017 CPS, we also find that there were 11.59 million U.S.-born children under age 18 with a foreign-born mother who arrived in 1982 or later. These children still live with their immigrant parents so determining the parent’s year of arrival is straightforward. Adding this number to second-generation adults whose parents arrived in 1982 or later creates an estimate of 16.03 million second-generation Americans (adults and minors) of post-1982 immigrants in the country in 2017.
Grandchildren of Post-1982 Immigrants. One additional number needs to be estimated to determine the full impact of immigration since 1982 — grandchildren. We find that in 2017 second-generation Americans born 1982 to 1999 had a total of 1.75 million children. Again, assuming that 50.7 percent of these second-generation American adults are the children of a post-1982 immigrant and applying that percentage to their children gives us 888,699 grandchildren of post-1982 immigrants. Second-generation Americans ages 15 to 17 had an additional 1,828 children in 2017. We estimate 92.9 percent of these children have post-1982 immigrant grandparents. In total, there were 890,527 grandchildren of post-1982 immigrants in 2017.
Estimating the Total Impact of Post-1982 Immigration. In sum, immigration from 1982 to 2017 added 52.7 million people to the U.S population — 35.78 million immigrants and 16.93 million descendants (16.03 million U.S.-born children and 890,527 grandchildren). The Census Bureau’s population estimates from 1982 show a U.S. population of 231,534,000, and population estimates from 2017 show a U.S. population of 325,122,128 in 2017 for a total increase in the U.S. population of 93,588,128. This means that immigration accounted for 56.3 percent of U.S. population growth from 1982 to 2017.
Limitation of this Analysis. The biggest source of potential error in this estimate is our assumption that the share of second-generation Americans born from 1982 to 1999 as shown in the 1999 CPS remains the same in 2017. It is possible that second-generation Americans with post-1982 immigrant parents have a different emigration rate than those born in this time period to pre-1982 immigrants. This would mean that our assumption that about half of adult second-generation Americans born from 1982 to 1999 to post-1982 immigrant parents is too high or too low in 2017. However, there is no obvious reason to think that emigration rates differ significantly based on parental year of arrival for adult children of the same age born in the United States to immigrant mothers. Moreover, the emigration rates would have to differ a good deal to significantly impact our estimates.