Daniel Willingham:

People considering the economic impact of school closings have primarily focused on lost wages and productivity due to parents missing work, but a much greater cost lies ahead. Years from now the U.S. economy will lose trillions when those students who have fallen behind during remote learning enter the workforce. Kids must make up for lost learning, and the best option is summer school.

Here’s the problem. Under normal circumstances, school makes kids smarter; it literally raises IQs by ensuring practice in critical thinking, and by teaching factual knowledge that gives kids something to think critically about. Research shows that there’s an IQ cost when a child misses a year due to illness. When jurisdictions increase the drop-out age, the average IQ of the affected generation increases. These and other data have alternative explanations, but when combined they show that students gain between one and five IQ points each year they attend school.

In addition, there’s excellent evidence that IQ is a good predictor of performance at work and of income. That’s why most economists describe money devoted to education as an investment, not an expenditure.