Reviewer Commends RAND Report on Charter Schools
May 27, 2009

Examination of eight states uses sound methods and provides honest presentation

Contact: Teri Battaglieri (517-203-2940);
Derek Briggs (303) 492-6320;

EAST LANSING, MI (May 27, 2009)—A new report from RAND finds that charter schools have only modest or insignificant effects on student achievement, student attainment, integration and public school competition. A review of the RAND report notes some weaknesses, but concludes that overall the report is of high quality and makes an important contribution to the empirical literature on charter school effectiveness.

The RAND report, Charter Schools in Eight States: Effects on Achievement, Attainment, Integration and Competition, was reviewed for the Think Twice think tank review project by Derek Briggs of the University of Colorado at Boulder, an expert on social science research methods.

RAND’s study found:

  • Insignificant effects on reading and math achievement in five jurisdictions and small negative effects in two others.

  • Positive effects for graduation rates and matriculation in college, but only for two jurisdictions for which there were data.

  • No evidence that charter schools skim higher-achieving students from traditional public schools, and no evidence that charters lead to increased racial or ethnic stratification.

  • No evidence of a “competition effect” leading to an improvement or decline in the scores of local traditional public school students when charters enter a particular educational marketplace.

“On the whole, the methods used in this report are exemplary,” Briggs writes in his summary. “The authors describe their statistical analyses in a transparent manner that makes it possible for readers to form their own opinions about the strength of the argument being advanced.”

Briggs does point out weaknesses that the data and analyses underlying the finding of no evidence that charter schools are skimming high-achieving students away from public schools or leading to increased racial/ethnic stratification. The study uses highly aggregated data, meaning that a great deal of stratification and skimming could exist but still not be seen by the approach used in the report. Individual schools can be segregated but when the data are collapsed (or “aggregated”), with all the school-level data mixed together in one large pot, the aggregated populations of students in charter schools and traditional public schools might look very similar.  

On the issue of achievement, the most defensible charter effects estimated in this study are based on data from students who switch to charters in middle school or high school after having attended a traditional public school. Briggs notes that while this choice may strengthen the study’s internal validity, it limits the study’s external validity.

Briggs raises various other concerns and questions, but concludes that on the whole, the report is, “sophisticated, thoughtful and even-handed."

Find Derek Briggs’ review and a link to the RAND report on the web at:

About The Think Twice Project
The Think Twice project provides the public, policy makers and the press with timely, academically sound reviews of selected think tank publications. It is a collaboration of the Education Policy Studies Laboratory at Arizona State University and the Education and the Public Interest Center at the University of Colorado at Boulder and is funded by the Great Lakes Center for Education Research and Practice.


The mission of the Great Lakes Center is to improve public education for all students in the Great Lakes region through the support and dissemination of high quality, academically sound research on education policy and practices.

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