Longitudinal effects of in-school and out-of-school homework on high school grades

Research has shown that time spent on homework is an important influence on school learning. Many students complete their "home" work in school, yet it is unclear whether homework's effectiveness varies depending on whether it is completed in school or at home. The purpose of this research was to determine the relative influence on students' high school grades of time spent doing homework in school as compared to time spent doing homework out-of-school. We used longitudinal data from the National Education Longitudinal Study to develop, cross-validate, and test a series of structural equation models of the effects of in-school and out-of-school homework on students' high school grades. Results suggest that out-of-school homework had a substantial effect on grades, whereas in-school homework had no such effect. This finding held across different definitions of homework, and when using achievement test scores as an alternative measure of school learning. The findings suggest that schools should encourage students to complete homework at home, rather than in school.