California's Charter Schools: 2008 Performance Update
June 2008 32 pages
Free Executive Summary
California's Charter Schools: 2008 Performance Update, EdSource's fourth annual analysis of the state's charter schools, yields findings that are similar to last year’s report. Both years' studies control for the size of schools and the backgrounds of the students they serve in order to estimate the effect of their status as charter or noncharter schools on student achievement.
Key Findings: Performance of Charters vs. Noncharters
Charter elementary schools have lower average API scores
The 196 charter elementary schools in this analysis are, on average, about 70% of the size of the noncharter elementary schools, and they serve somewhat more advantaged students.
After adjusting for differences in school size and School Characteristics Index (SCI) values, charter elementary schools score 9 points lower on the API, due mainly to charter students' scores on the California Standards Test in mathematics, which are lower by statistically significant margins. But when the 25 nonclassroom-based charters are excluded from the analysis, charters' deficit on the API disappears, the difference in math shrinks, and their advantage in English grows slightly.
Charter middle schools outperform noncharters
The 57 charter middle schools are about one-third the size of noncharters on average, and they serve more disadvantaged students.
After adjusting for differences in school size and SCI values, charter middle schools score 45 points higher on the API. The findings are consistent across other performance measures and have also been stable over time.
Charter high schools have higher API scores but lower math scores than noncharters
The 130 charter high schools are about one-fifth the size of noncharters, on average, and generally have lower SCI values.
After adjusting for differences between charters and noncharters in school size and SCI values, charter high schools score 14 points higher on the 2007 Growth API, despite lower scores in mathematics. When the 50 nonclassroom-based charters are excluded, charter high schools score higher than noncharters on all measures, including mathematics.
Along with these findings, this analysis offers a wealth of other comparisons and insight on the state's charter schools including:
- Within Charter Comparisons—CMO Charters vs. Non-CMO Charters
A substantial portion of the growth in the state's charter school segment in recent years has come from the creation and expansion of charter management organizations (CMOs). These schools represent nearly one-fifth of the charters in this study. CMO charters, on average, outperform other charters; but not all CMO-run charter schools are high achievers.
- District Profiles: Los Angeles, Oakland, and San Diego Unified School Districts
In three of the state's largest districts, Los Angeles, Oakland, and San Diego, charter schools have become relatively common. This report contains separate performance comparisons of charters and noncharters in these districts.
This summary only skims the surface of the information available in this report. You will also find detailed "Vital Stats" on the state's charter schools as well a look at how closely districts are matching the state's new achievement benchmarks for charter school renewal.
EdSource thanks Reed Hastings for his support of our annual work to independently and impartially analyze and report on California charter school performance.
