Independent, objective, nonpartisan research
Report · July 2019

Achievement in California’s Public Schools: What Do Test Scores Tell Us?

Paul Warren and Julien Lafortune

Two major reforms have transformed California’s K-12 education system over the past decade. To revamp English and mathematics instruction, the Common Core standards were adopted in 2010, with district implementation beginning several years later. In 2013, the Local Control Funding Formula (LCFF) was enacted to increase funding for disadvantaged students, reshape the state’s K-12 accountability system, and expand local control over school spending. There is now concern that these reforms are failing to improve student outcomes fast enough. To evaluate these concerns, this report examines California’s performance on two tests of English and mathematics-the Smarter Balanced Assessment Consortium (SBAC) tests and National Assessment of Educational Progress (NAEP).

Overall, we find that California’s performance is mostly headed in the right direction. Specifically, we find:

  • Significant progress in English. Both tests indicate that California made large gains in English scores between 2015 and 2018. On the SBAC, the percent of third-graders scoring at proficient levels increased 10 percentage points. Proficiency also increased 10 points as students progressed from third to sixth grade. NAEP data also reflects major gains: reading scores (adjusted for the share of low-income students) are now near the national average.
  • Stalled gains in mathematics. Both tests suggest that Common Core math standards are not yet generating improved student performance. Third-grade SBAC scores have improved 9 percentage points, but growth in later grades is inconsistent. However, California’s gains are larger than in Oregon and Washington, which also use the SBAC. NAEP math scores improved fairly consistently from 2003 to 2011 (before Common Core) and then flattened. California’s relative performance among states is mostly unchanged.
  • Persistent income achievement gaps. District-level SBAC analysis shows no relationship between growth and district income in English. In math, growth is slower in lower-income districts: gaps increase as students move through the grades. NAEP data reveal a similar pattern.
  • Slow change is to be expected. The NAEP data also show that average achievement at the state level does not change quickly. Improvement usually comes in small sustained increments, which, over time, can make a significant difference for students.

The conflict between our goals for students and the pace of change is important to recognize. Large leaps in performance are unlikely from year to year. Our findings suggest, though, areas for state action that could hasten the improvement process. There are almost no state funds for improving math instruction in grades 4 to 8, for instance, and the lack of progress in this subject argues for providing additional help to districts. In addition, the success of both reforms depends upon state support for low-performing districts, as the process of improving instruction is intensely local. Ensuring that the state’s system of support for struggling districts is adequately funded and operating effectively is crucial to the success of our K-12 system.

The state also needs to ensure and expand the availability of accurate and meaningful performance data. Currently, the California Department of Education does not publish data on the growth of student scores from year to year. Yet understanding K-12 performance-the progress of schools, districts, and student subgroups-requires accurate growth data. Parents, community members, and educators need good data to provide feedback on the effect of local improvement efforts. Policymakers and the public also need this information to assess the impact of recent K-12 reform efforts. Without it, conclusions will be based on anecdotes and impressions rather than evidence.


K–12 Education Population