The Relationship Between Homework and Achievement—Still Much of a Mystery

Despite the long history of homework and homework research, the role that homework plays in enhancing student achievement is, at best, only partly understood. In this review, we give an overview of twentieth-century homework research and discuss the reasons why the relationship between homework and achievement remains unclear. We identify the operationalization of homework and achievement and the problematic handling of hierarchically ordered data as two important factors affecting the validity of many of the studies performed over the last century. We then describe a new generation of homework studies using multilevel modeling to deal with hierarchically nested data. Finally, we argue that homework research should be more closely connected to well-founded psychological theories of learning and instruction, and we offer three potential links (theories of instruction time, self-regulation theory and expectancy-value theory, and teaching behavior).