*Class size is an important determinant of student outcomes, and one that can be directly determined by policy. All else being equal, increasing class sizes will harm student outcomes.
* The evidence suggests that increasing class size will harm not only children’s test scores in the short run, but also their long-run human capital formation. Money saved today by increasing class sizes will result in more substantial social and educational costs in the future.
* The payoff from class-size reduction is greater for low-income and minority children, while any increases in class size will likely be most harmful to these populations.