Heat and Learning

This working paper from the National Bureau of Economic Research provides a unique large-scale analysis and a memorable finding about the impacts of heat exposure on student achievement: without air conditioning, each 1° F increase in school year average temperature reduces the amount students learn that year by 1%.
The authors mined data from 10 million American 10th-graders who took the PSAT exam. To estimate the causal impact of cumulative heat exposure, they linked local daily weather data to the test scores of students in the high school classes of 2001-14. By focusing on students who took the exam multiple times, they were able to track variations in the performance of the same students in years when they had been exposed to different average temperatures. The authors found that students learned less when they were exposed to hotter school days in the year prior to a test, with extreme heat being particularly damaging. These effects were greater for lower-income and minority students.
The straightforward pattern of the effects was matched by evidence of a straightforward solution: air conditioning. By comparing schools with and without AC, the authors found that it almost entirely offset the effects of increased outdoor temperatures. In conclusion, they suggest that the benefits of school air conditioning likely outweigh the costs, more so as average annual temperatures continue to rise and extreme heat events become more frequent.