California charter schools trailed traditionally run public schools, but charters showed stronger year-to-year improvement, according to results from the state's annual testing and accountability system.
Within the Los Angeles Unified School District, charter middle and high schools -- independently run but publicly funded campuses -- scored higher than district campuses, according to separate evaluations of public school performance.
District officials, however, said the analyses, conducted separately by the California Charter Schools Assn. and The Times, were misleading.
The findings are based on schools' scores on the Academic Performance Index, the state's method of assessing public school performance. Schools are graded on a scale of 200 to 1000 based on standardized tests administered each spring in math, English and other subjects.
The Times found that California charters as a whole scored 700, an average gain of 28 points over last year's results, while traditional schools posted 719 and showed a 20-point improvement. That pattern is similar to a year ago, when charters scored about 20 points lower than their district-run counterparts but showed a somewhat better improvement rate.
But the traditional schools' advantage is limited to the elementary level, where they exceeded charters 753 to 743. In secondary schools, where gains in student achievement have remained well below those in the earlier grades, charters outdistanced district schools, 742 to 717 for middle schools and 633 to 622 for high schools.
In Los Angeles Unified, charters exceeded district schools, 715 to 677; their scores grew by 30 points overall, while district schools grew by 20.
The findings are unlikely to quiet the debate over whether charters, which are granted substantial freedom from the requirements governing traditional schools, do a better job; a handful of earlier studies has produced somewhat conflicting results or found the differences to be relatively small.
Priscilla Wohlstetter, professor and co-director of the Center on Educational Governance at USC, said reviews of school performance shed light on ways the charter movement, more than a decade old in California, can contribute to broader school reform issues.
"We are seeing some evidence that this reform is working, and maybe we can benefit from this longevity," said Wohlstetter, who is overseeing a study of promising practices at charters around the state.
