Of all the relationships in global development data, this is one of the most consistent. Plot fertility against university enrolment for the 150 countries with both figures and the correlation is −0.66 — education up, births down, with remarkably few exceptions.

Squared, that is about 43% of the variation in national fertility accounted for by a single education indicator. For social data, that is a strong signal.

The two ends

The global fertility range is wider than most people assume. Chad records 6.03 births per woman. Macao SAR records 0.58 — a tenfold gap, and the low end is now far below the replacement rate of roughly 2.1 that keeps a population stable without migration.

The countries with the lowest fertility and the highest enrolment:

• Macao SAR — 0.58 births per woman, tertiary enrolment 141.9%
• South Korea — 0.75 births, 111.9%
• Hong Kong SAR — 0.84 births, 120.1%
• Singapore — 0.97 births, 97.3%
• Ukraine — 0.99 births, 87.2%
• Chile — 1.14 births, 110.2%

And the opposite corner:

• Angola — 5.05 births per woman, tertiary enrolment 10.0%
• Burundi — 4.79 births, 6.4%
• Tanzania — 4.54 births, 4.0%
• Benin — 4.48 births, 10.2%
• Madagascar — 3.91 births, 6.2%
• Malawi — 3.59 births, 2.7%

Wait — how is enrolment above 100%?

This trips up almost everyone, and it is worth understanding before you draw any conclusions from the numbers above.

Tertiary enrolment here is a gross enrolment ratio: total enrolled students divided by the population of the official university-age cohort. Students outside that age band — mature students, people repeating years, international students — count in the numerator but not the denominator. So the ratio can exceed 100% without anything being wrong.

Greece tops the dataset at 165.1%, which reflects a large population of students outside the standard age window rather than a country that has educated more people than exist. Suriname sits at the bottom on 2.6%.

The practical consequence: treat the high end of this indicator as "very high participation" rather than as a precise ranking. The gap between 97% and 142% is not meaningful in the way the gap between 4% and 40% is.

Why the relationship holds

The correlation is robust, but correlation is where the data stops and interpretation begins. The mechanisms demographers generally point to:

Timing. Years spent in tertiary education are years not spent having children, and fertility declines sharply with maternal age. Delay alone reduces completed family size even when intentions don't change.

Opportunity cost. Higher education raises earning potential, which raises the cost of time away from paid work. This effect is much stronger for women, and female enrolment tracks fertility decline more tightly than male enrolment does.

Child mortality. Educated populations are also populations where children reliably survive, which changes how many births are needed to reach a desired family size. Historically this is one of the largest single drivers of fertility transition.

Contraceptive access and autonomy. Education correlates with both, and both directly affect fertility.

Note that these run in several directions at once. Countries that expand universities are usually also urbanising, getting richer, and improving child survival simultaneously. Nothing in this dataset can isolate education as the cause — it can only show that the two move together.

The South Korea problem

South Korea is the case that has moved from academic interest to national emergency. At 0.75 births per woman against 111.9% tertiary enrolment, it has among the world's most educated populations and the lowest fertility of any large country.

At that rate each generation is roughly a third the size of the one before it. The Korean government has spent heavily on incentives for two decades and the number has continued to fall, which is the strongest available evidence that the drivers here are structural — housing costs, working hours, the cost and intensity of education itself — rather than something a birth bonus can fix.

Ukraine's 0.99 should be read separately: wartime displacement affects both the numerator and the denominator of a fertility statistic, and figures for a country at war carry unusual uncertainty.

What this means going forward

Roughly two-thirds of the world's population now lives in a country below replacement fertility. The high-fertility countries in this dataset are concentrated in sub-Saharan Africa, and every one of them also has tertiary enrolment under 15% — which, on the pattern above, is precisely where the sharpest declines tend to come next.

Explore the full maps for fertility rate by country and tertiary enrolment, or try the daily map game. Source: World Bank Open Data, 2024 and 2025.