How Much Would Continued Low Fertility Affect the US Standard of Living?

I assess the effect of continued sub-replacement fertility on age-adjusted consumption per capita. Channels assessed include transfers from working-age adults to children and the elderly, the effect of the labor force growth rate on required capital investment, sustainability of government debt, the interaction of population size with fixed natural resources (including a clean environment), and the effect of population size on the speed of technological progress. To isolate the effect of low fertility from other ongoing demographic changes, I use simulation models as well as projections from the United Nations and Social Security Administration that vary fertility rates while holding other factors constant. My main finding is that the impact of low fertility is likely to be negative but small. In addition, this negative impact arrives only after a long adjustment period. An increase in fertility back to the replacement rate would lower the standard of living for several decades.