The majority (70 percent) of districts have implemented Common Core, new academic standards in English language arts and math adopted by California in 2010, a report from the Public Policy Institute of California shows. About a third of districts have not yet started, and rural districts are less likely than urban or suburban districts to be teaching the new standards.

In districts that have adopted the standards, Smarter Balanced test scores for middle school math and English language arts improved slightly, and increases were larger among low-income and Latino students.