The study featured in this What Works Clearinghouse (WWC) Quick Review examined the effect of charter school attendance on annual student achievement growth in math and reading. The study analyzed data from a large sample of students in grades 4 through 9 in Indiana from 2004 to 2008. The study found that charter school students' annual math score growth was 0.07 standard deviations higher, and that their annual reading test score growth was 0.05 standard deviations higher, than a group of similar students attending traditional public schools. These differences were statistically significant, and the WWC interprets them as roughly equivalent to moving a student from the 50th to the 53rd percentile in math and from the 50th to the 52nd percentile in reading. The study also found that, in general, charter school students with reading and math scores in the bottom half of the achievement distribution the previous year had significantly higher gains than their comparison counterparts. The research described in this report meets WWC evidence standards with reservations. (Contains 2 footnotes.) [The following study is the focus of this "Quick Review": "Charter School Performance in Indiana."]