This impact study addresses a key challenge in K–12 education—despite a national push for high-quality instructional materials (HQIM), there is limited causal evidence on how specific curricula affect student outcomes. This study provides the first causal evidence on the impact of the widely adopted Illustrative Math (IM) curriculum, using data from 71 Massachusetts middle schools.

Researchers found that schools adopting IM prior to the COVID-19 pandemic significantly outperformed comparable schools, particularly in grades 7 and 8, by the third year of implementation. In contrast, schools that adopted IM during or after the pandemic showed no meaningful improvement relative to those using other high-quality math programs.These findings highlight that the effectiveness of HQIM depends not only on the curriculum itself but also on the conditions supporting its implementation.

WestEd is recruiting for a national study designed to help instructional leaders understand and support high-quality curriculum implementation and improve mathematics teaching and learning in the middle grades. Learn more at https://imes.wested.org/