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Impact Evaluation of Charter School Strategies

Contract Information

Current Status:

This study has been completed.


September 2003 – July 2010



Contract Number:



Mathematica Policy Research
University of Washington

The Public Charter Schools Program (Title V, Part B, Subpart 1 of the Elementary and Secondary Education Act, as reauthorized by the No Child Left Behind Act) supported the planning, development, and initial implementation of charter schools in states and communities across the U.S., with funding of $216 million in Fiscal Year 2009. A key component of both the federal program and the charters that schools signed with authorizers in their states was a promise to reach milestones for students' academic achievement.

There remains ongoing debate about the extent to which charter schools improve students' academic achievement, with much of the evidence based on descriptive or quasi-experimental studies that cannot fully separate the effects of charter enrollment from the characteristics of students who choose to attend those schools. Policy interest has shifted from a sole focus on "are they effective" to the policy levers (e.g., the level of autonomy, types of authorizers) and school characteristics that might make them more effective. This evaluation focuses on these issues using rigorous random assignment methods to provide credible estimates of impact.

  • What are the impacts of charter schools on student achievement, other indicators of performance, and parent and student satisfaction?
  • To what extent does the degree of autonomy or policy environment under which charter schools operate seem to influence their effectiveness?
  • In what ways are charter schools and the sending regular public schools different? What role do these school factors or characteristics play in determining student outcomes?

About 40 charter middle schools in 15 states that had more applicants than space available participated. Among applicants to each charter school, about 30 students in the entry grade were randomly assigned through lotteries to be admitted to the school (treatment group) or to attend another school of their own choosing (the control group). Schools and students were recruited in early 2005 and in early 2006. Two years of data were collected for students on both groups, including student records, annual test scores, and surveys of students, principals, and parents.

A report, titled The Evaluation of Charter School Impacts: Final Report, along with a study snapshot of findings, was released in June 2010.

A restricted-use file containing de-identified data is available for the purposes of replicating study findings and secondary analysis.

A follow up issue brief, titled "Do Charter Middle Schools Improve Students' College Outcomes?", was released in April 2019.

  • On average, participating charter middle schools were neither more nor less successful than traditional public schools in improving math or reading test scores, attendance, grade promotion, or student conduct within or outside of school. Being admitted to a study charter school did significantly improve both students' and parents' satisfaction with school.
  • Charter middle schools' impact on student achievement varied significantly across schools, with those in urban areas and serving higher proportions of low-income and low-achieving students more effective (relative to their nearby traditional public schools) than were other charter schools in improving math test scores.
  • There was no significant relationship between achievement impacts and the charter schools' policy environment. However, enrollments and the use of ability grouping in math or English classes were associated with less negative impacts on achievement.

Follow-up study:

  • Being admitted to a charter middle school in the study did not affect college enrollment or degree attainment. On average, 69 percent of both students admitted to charter schools and students that applied but were not admitted enrolled in some type of college by December 2017, or 3–8 years after they were expected to graduate from high school. On average, 48 percent of students admitted to charter schools and 47 percent of students that applied but were not admitted had a degree or were still enrolled as of December 2017.
  • Individual charter middle schools' success in improving college outcomes was not related to their success in improving middle school achievement. The schools that improved middle school achievement — charter schools in urban areas and those serving economically disadvantaged students — were not consistently more successful than others in boosting college enrollment and completion.