A new meta-analysis of 38 studies on charter school performance finds the best available research "encouraging." In the report for the Charter School Leadership Council, author Bryan C. Hassel says studies tracking individual students over time are the most informative because the method allows researchers to identify the schools' value.
Among the nine studies in this category is the 2004 Goldwater Institute study, which examined test scores of 60,000 Arizona students attending 873 charter and traditional public schools statewide over a three-year period. Findings indicate that Arizona charter school students, on average, began with lower test scores than their traditional public school counterparts, and showed overall annual achievement growth roughly three points higher than their non-charter peers. However, achievement growth varies by grade level. Goldwater Institute analysts are building on this research by conducting a bi-annual progress report tracking more students over longer periods of time.