Choosing the right curriculum is one of the most consequential decisions a district can make, particularly in math and for students who have historically been underserved. This brief examines the 5-year impact of the adoption of the Illustrative Mathematics (IM) curriculum by Oakland Unified School District (OUSD) across all 11 of its traditional middle schools, comparing student achievement on the California state math assessment to that of similar non-IM schools statewide from 2018–19 through 2023–24.

Findings show meaningful, positive effects across all three middle school grade levels, with the strongest results emerging after 3 or more years of implementation. While math scores declined across California during the pandemic, OUSD middle schools implementing IM significantly outperformed comparable non-IM schools statewide in grades 6–8 beginning in the third year of implementation, with effect sizes ranging from 0.28 to 0.53 standard deviations. The findings point to the potential of a high-quality, problem-based curriculum as a lever for improving math outcomes in diverse, urban districts.