CBO expects the population to be 2.8 percent smaller (equaling 11 million fewer people) in 2050 than the agency projected last year (see Figure A-1). Those changes result from revisions to the agency’s projected rates of fertility, net immigration, and mortality.
CBO projects that the total fertility rate will remain at its most recent historical value of 1.7 children per woman in 2020 and decline to 1.6 children per woman in 2021 in response to the economic effects of the pandemic.2 CBO expects the fertility rate to gradually rise through the remainder of the decade, averaging 1.8 children per woman from 2020 to 2030 and 1.9 children per woman in the following two decades.
Projections of Fertility. CBO projects fertility rates on the basis of the agency’s assessment of historical fertility trends, the effects of the pandemic, and other factors. Though fertility rates tended to decline during recessions and rebound during recoveries in the two decades preceding the 2007–2009 recession, the fertility rate did not recover after that recession. That rate was 2.0 children per woman, on average, in the 20 years before the recession, peaking at 2.1 in 2007. The rate was 1.7 children per woman in 2019 (the most recent year for which data are available). The decline was largely attributable to lower fertility rates among women age 24 or younger.3
CBO projects the fertility rate to average 1.9 births per woman from 2020 to 2050, which is below the replacement rate—the fertility rate required for a generation to exactly replace itself—of 2.1 children per woman. CBO’s projections of fertility rates are consistent with the recommendation made to the Social Security Advisory Board by its 2019 Technical Panel on Assumptions and Methods.4