Measuring Charter Performance: A Review of Public Charter School Achievement Studies is the sixth annual research synthesis which continues to assess the available research on charter school achievement. Sixty-three new studies were added this year, making a total 203 research studies in the report. These studies all meet the National Alliance for Public Charter Schools (NAPCS) standard for inclusion in the report: all compare student achievement in charter and traditional public schools, use in-depth research methods and examine a significant segment of the charter sector. NAPCS classifies these studies according to their methodology and rigor, and uses the results to describe charter school achievement. The analysis shows no single study can definitively describe how charter schools are performing in a district, state or at the national level. However, the emerging picture is largely positive for charter school advocates: The findings from studies using the best data and most sophisticated research techniques suggest that more often than not charter school students are experiencing similar or greater achievement gains than students in comparable traditional public schools. It is with great pleasure that we share these profiles with members of the education-reform community who should reference them, confidently, to better inform their work.