Lower birth rates in young girls correlate with higher worker productivity.
Comparing Output per worker, GDP constant 2021 international $ at PPP (ILO modelled estimates) with Population ages 00-04, female, per capita across 185 countries, 2025–2027.
- Rank correlation
- -0.80
- Holding size constant
- -0.66
- Countries compared
- 185
- Period
- 2025–2027
What might link these
This suggests a potential inverse relationship between the proportion of very young females in a population and economic output per worker. A possible confounder is the overall level of development, as more developed nations often have lower birth rates and higher productivity.
Why this is not proof of anything
This is a correlation across countries, not an experiment. It cannot show that either indicator causes the other, and both may simply follow a third thing. This correlation does not imply that lower birth rates cause higher productivity, or vice versa.
The second figure above repeats the measurement with national population and income held constant. It is the more conservative number: a relationship that largely disappears there was mostly telling you that larger, richer countries have more of most things.
How this was measured
Both indicators were ranked across every country reporting each, and the two rankings compared — ranks rather than raw values, because a handful of very large countries can otherwise manufacture a relationship on their own. The calculation is arithmetic over figures already published on this site; the commentary above is drafted from the two indicator names and the resulting coefficients.