Do lower birth rates raise output per worker decades later?
Core argument: A 1pp lower birth rate 20 years earlier is associated with 22 log points higher GDP per worker at t+20 and 29 log points by t+40, roughly 0.73 percentage points faster annual growth over the 40-year interval.
Figure 3 traces out how GDP per worker evolves following a 1pp increase in birth rates at t−20. Since cohorts born at t−20 (e.g., 1970) do not enter the working-age population until t = 0 (e.g., 1990), we should observe no response before t = 0; [indeed] the estimated coefficients are ~0 and statistically insignificant before t = 0. Beginning at t = 0, however, higher birth rates are associated with lower GDP per worker, and the negative effects grow progressively larger over time. For example, a 1pp lower birth rate at t−20 is associated with 22 log points higher GDP per worker at t+20 and 29 log points higher by t+40. The latter corresponds to roughly 0.73 percentage points faster annual growth over the 40-year interval. We find that lower birth rates are associated with more labor-saving patents and a growing share of high-tech industries across countries and US commuting zones [Figure 11]. They are also predictive of higher TFP growth across countries and US industries and increased patenting in ICT and broader automation technology classes. Using cross-country variation in WWII-era military and civilian deaths, we present suggestive evidence that the positive growth effects of falling birth rates are primarily driven by the scarcity of younger workers rather than by reductions in population per se [Figure 14]. [Editor’s note: the paper does not grapple with the fiscal consequences of an aging population.]

