There are currently more job openings than unemployed people in the United States. The boosted scarcity of workers could be partly alleviated by an increase in legal immigration, but the current problem is exacerbated by a decline in the growth of the immigrant population. Diane Swonk, Chief Economist at Grant Thornton LLP, recently tweeted a figure showing that 1.9 million additional immigrants would have populated the United States over the 2017–2021 period if net migration had continued to grow according to the Census Bureau’s 2016 estimates. Swonk’s estimate is in the right direction, but she is too optimistic as the decline in the growth of the immigrant population is likely much greater.

We decided to replicate her results going back to 2008 using Census Bureau data and using her estimate for the increase in the stock of immigrants in 2021. Our results are in Figure 1. The yellow line shows the actual change in the net immigrant number (immigrants minus emigrants) annually, which increases sharply from 2010 to 2015, levels off in 2016, and then declines thereafter (Figure 1). We produced two counterfactuals.

The first is a mirror of Swonk’s counterfactual, which roughly continues the 2016 trend in net migration out to 2021 and is represented by the gray line (Figure 1). We estimated about 2.4 million more immigrants on net during that time whereas she estimated about 1.9 million.

For the second counterfactual, we continued the linear upward trend from 2014–2015 out to 2021, represented by the dashed grey line (Figure 1). In this counterfactual about 4.8 million additional immigrants would have cumulatively settled in the United States, assuming no leveling off in growth in net migration in 2016 and no decline thereafter.

The numbers in Figure 1 include all foreign-born residents such as lawful permanent residents, naturalized Americans, those on temporary resident and work visas, and illegal immigrants. The decline in net immigration is mostly due to the fall in legal immigration. In these counterfactuals where the net cumulative increase in the immigrant population would have been 2.4 million to 4.8 million higher, not all of the immigrants would have been workers. With an average labor force participation rate of about 64.5 percent in 2020, the increase in the net immigration numbers would have resulted in about 1.5 million to 3.1 million additional workers in the United States.

The radical decline in the growth of the immigrant population in 2009 and 2010 was due to the negative effects of the Great Recession and the passage of numerous state-level immigration enforcement laws that prompted many illegal immigrants to leave the United States, reducing the increase in the immigrant population. The decline in the annual increase of immigrants since 2016 makes it look like the United States has suffered a prolonged period of slow growth or economic contraction.

Diane Swonk’s figure is a useful way to think about problems in the U.S. economy that have been exacerbated by the decline in immigration. Her figure paints a grim picture for immigration, but it is likely much worse than she estimates. The cumulative decline in the growth of the immigrant population over the 2016–2021 period is between 26 percent and 251 percent greater than she estimated.