Results released Wednesday show 49 percent of public schools reached or exceeded the state target on the Academic Performance Index or API. That's a 3-percent increase over last year.
A school's API is determined by a student's performance on statewide assessment tests. Despite the improvement, officials say 913 more schools could face sanctions under the federal No Child Left Behind law for failing to reach government benchmarks.
California now has nearly 3,900 schools that are required to take action to improve test scores.