Students who learn in hotter classrooms perform worse on college admissions tests, according to a new .
About 42 percent of U.S. classrooms lack any or adequate air conditioning, according to the research led by Joshua Goodman, a Harvard University microeconomist studying human capital and education policy.
The researchers tracked 10 million secondary students who took the PSAT multiple years between 2001 and 2014. On average, students improved their score by about a third of a standard deviation by taking the test more than once. But the researchers also found that weather played a role from one test to the next: A student鈥檚 performance dropped by nearly 1 percent of a year鈥檚 worth of learning for every 1 degree Fahrenheit hotter the outside temperature was during the school year before a student took the test.
Compared to school days in the 60s temperature range, every additional school day in the 90s was associated with 1/6 of a percent of a year鈥檚 learning, and each day above 100 degrees led to an effect that was 50 percent larger. While that seems small, it adds up in districts where local weather has grown warmer in recent years.
鈥淧hysiologically, as the temperature goes above 70 degrees, that鈥檚 where people start to feel uncomfortable,鈥� Goodman said. 鈥淪tarting above 70 degrees, the students start to learn less and, basically the hotter it gets after that, the worse that is for learning.鈥�
The researchers found, however, that more than 70 percent of the test-score drop for students with hotter school years disappeared when they attended schools with air conditioning.
As much of the nation鈥檚 school infrastructure ages, administrators have come under more scrutiny for maintenance issues. Earlier this month鈥攁fter intense public criticism for heating and cooling system problems that led to 100-degree classrooms last September and 40-degree rooms during the winter鈥� the Baltimore public school system announced it would dismiss school three hours early at about 70 schools that lack adequate air conditioning on days when the temperature in most classrooms in most buildings reaches 85 degrees or the outside heat index reaches 100 degrees by 10:30 a.m. And schools in St. Paul, Minn., had to deliver more than 2,000 bottles of water and hundreds of fans following a heat wave that spiked 101 temperatures in classrooms and sent dozens of students to the nurse鈥檚 office for heat exhaustion.
For most of the 20th century, most U.S. schools let out in early June and returned after Labor Day. While that鈥檚 still the case in some areas, efforts to extend learning time鈥攑articularly for traditionally disadvantaged students and chronically struggling schools鈥攈ave led to earlier start dates in August and later end dates in June.
Worsening Achievement Gaps
The new study suggests lack of air conditioning could counteract efforts to use longer school schedules to help close achievement gaps; researchers found the impact of heat on student learning was three times higher for low-income, black, and Hispanic students than on their white or wealthier peers. 鈥淧art of it could be that more advantaged teachers and families have a greater ability to compensate for students鈥� lost learning time,鈥� Goodman said.
鈥淲e could provide evidence that student鈥檚 learning is suffering because of heat, but we can鈥檛 pinpoint exactly how they鈥檙e losing learning time. Are they losing time because the school is closing or they鈥檙e being moved to different parts of the building, or because they鈥檙e in the same classroom but they鈥檙e sweaty and distracted?鈥� he said. 鈥淔rom a public policy perspective, I don鈥檛 think we really care. All of those are ways in which heat is screwing up the time students have to learn, and in all those cases having better infrastructure would almost certainly alleviate that problem.鈥�
The findings only apply to high schools, but Goodman said the researchers hope to look next at how temperature changes affect younger students, as well as how the heat could affect other aspects of schooling, like student behavior. Prior studies outside of schools have found heat waves are associated with higher rates of crime.
鈥淲hat I take away is that there is a clear justification for our further investment in the infrastructure of our schools,鈥� he said. 鈥淪eparate from issues of equity, from a purely selfish perspective, you should be investing more in making students physically comfortable and able to learn.鈥�
A separate by Penn State University鈥檚 Center for Evaluation and Education Policy Analysis found students learned reading and math best at classroom temperatures between 68 degrees and 74 degrees Fahrenheit. 鈥淭o maintain such a temperature in every classroom within a school, teachers typically need to be able to control the temperature in their own classroom,鈥� the report recommends, adding, 鈥淎t the very least, teachers should be able to control the temperature of small blocks of classrooms that receive the same amount of sunlight and have similar exposures to outside temperatures.鈥�
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