Learning is Inhibited by Heat Exposure, both Internationally and within the United States

This technical paper from Nature Human Behaviour summarizes large-scale studies of heat exposure and student achievement. Crossing standardized test data from 58 countries and 12,000 U.S. school districts with local weather data, the authors found a clear global pattern: as the number of hot school days (>80° F) increases, learning outcomes decline.

The findings are based on two analyses, each of which is described in detail and illustrated with figures and maps. The first analysis used the test scores of a demographically-representative sample of 15 year olds in 58 developed and developing countries that participated in the Programme for International Student Assessment (PISA) between 2000 and 2015. The second analysis used standardized test scores from over 12,000 U.S. school districts, taken from the Stanford Education Data Archive (SEDA). Both analyses employed quasi-experimental research methods with statistical controls designed to isolate the causal impact of heat exposure on learning. These methods are cataloged and explained in the paper.
The authors discuss implications of their findings that are both educational and economic. As the academic achievement of a nation’s young people – aka its “human capital accumulation” – is a driver of economic growth and mobility, then a warming climate that hinders students’ opportunity to learn is a drag on that nation’s future economic development. This, in turn, suggests that public investments to make school facilities more heat-adapted, resilient, and sustainable will yield increasing benefits over time. Resilient facilities may also produce greater positive effects on student outcomes than other strategies for school improvement; for example, the authors find that the unmitigated impact of an additional 30 hot school days in a year would more than offset the expected benefits of reducing class sizes.