Homework and students' achievement in math and science: A 30-year meta-analysis, 1986-2015

•There was an overall small and positive relationship between homework and academic achievement in math/science.•The relationship was stronger for elementary and high school students than for middle school students.•The relationship was shown to be the strongest in the studies involving US students.•The effect sizes varied among the studies with different homework indicators.•The mean effect sizes from dissertation were the highest, and those from the journal articles were the lowest.

In the current investigation, research conducted since 1986 were synthesized to examine the homework - achievement relationship in math/science, and to examine a range of factors that could have moderated this relationship. Our investigation revealed that there was an overall small and positive relationship between homework and academic achievement in math/science. Our investigation further revealed that the homework - achievement relationship in math/science was stronger for elementary and high school students than for middle school students. In addition, the homework - achievement relationship in math/science was shown to be the strongest in the studies involving US students, whereas it was the weakest in the studies involving Asian students. We discussed possible explanations for these and other findings, and the implications for future research directions.