¹ Caution must be used when interpreting the estimates reported here because the survey method used to ask about time spent on homework per week differed in 1980 and 2002. The 1980 survey asked about “homework” without differentiating between homework completed in school and out of school; it also used the categories reported here as predefined response categories. The 2002 survey asked students to report both in-school and out-of-school homework and used an open-ended response format. The 2002 responses were then grouped into the 1980 response categories.

SOURCE: Cahalan, M., Ingels, S., Burns, L., Planty, M., and Daniel, B. (2006). United States High School Sophomores: A Twenty-Two Year Comparison, 1980–2002 (NCES 2006-327), data from U.S. Department of Education, National Center for Education Statistics (NCES), High School and Beyond Longitudinal Study of 1980 Sophomores (HS&B-So:80) and Education Longitudinal Study of 2002, Base Year (ELS:2002).