The purpose of this study was to investigate fifth-grade student achievement in Ohio public charter schools as compared to student achievement in traditional public schools, and to determine whether the performance of charter schools changed over time. Research questions asked 1) how does student achievement in Ohio's public charters compare to that of traditional public schools, and 2) do Ohio's charter schools show increased student achievement over time? Drawing on an approach used by Miron (2002; 2005; 2007), adjusted, or filtered scores were created by using the slope and intercept obtained from two regression models (one for reading and one for mathematics) that were performed with traditional public schools for each of the six years of the study. This approach allowed the investigation to control for the influence of student achievement predictors generally recognized in the research literature: socioeconomic status, ethnicity, special needs status, and school size. The result produced three measures for each of the schools: actual scores, predicted scores based on the adjustment for demographic variables and the computed difference between the actual and predicted scores. Score differences were then compared and analyzed over time to determine whether the gap between public charter and traditional public school achievement changed. As public charter schools matured, and as the number of operational public charters increased, T-test results confirmed that charter school performance in Ohio improved. In the sixth year of the study, the level of charter school achievement approximated that of traditional public schools. Results of the study have policy implications regarding public charter school funding, methods to properly assess school-wide student achievement, and the equitable treatment of both public charter and traditional public schools with regard to sanctions related to student achievement outcomes. Further, study findings can be used to guide future research about public charter schools in terms of methodologies and research models that might extend the line of inquiry. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]