Probably the most commonly cited national study on charter school performance is a 2013 study by the Center for Research on Education Outcomes (CREDO) at Stanford. It analyzed charter results between 2008 and 2011 in 27 states, covering over 95% of the students in charter schools. The report found small benefits to attending a charter school in terms of reading achievement and no noticeable difference in math achievement.

A 2014 meta-analysis that included 52 high-quality studies published from 2001 to 2013 of charter school performance found that charter schools, on average, had positive impacts on students’ math achievement relative to traditional public schools in most grade groupings. No statistically significant differences were found in reading.

While the overall story of charter school performance is positive, averages hide a lot of variation. There are substantial differences between different schools’ performance.

There are noteworthy differences among states, cities, networks of schools and individual schools. Some are providing students with high-quality choices and helping them to excel academically — while others are not helping students to accelerate their learning.

Some charter schools are independent; others are part of not-for-profit organizations that have unique philosophies and approaches that they use to operate multiple charter schools. The Knowledge Is Power Program (KIPP) is a network of charter schools that currently serves 70,000 students in 183 schools in 20 states.

Mathematica Policy Research’s 2013 study found that the average impact of being enrolled at a KIPP middle school on student achievement in math, reading, science and social studies is “positive, statistically significant, and educationally substantial.”

The study found that after three years of enrollment in a KIPP middle school, students learn the equivalent of about 11 additional months in math than their traditional public school peers. In reading, students gain an advantage of 8 months of additional growth over three school years. In science, they gain a 14-month advantage, and in social studies, they gain an 11-month advantage.

Twenty percent of the 500 top high schools on the U.S. News & World Report’s Best High Schools List are charter schools. U.S. News calls these schools “gold medal schools.” (For reference, only 6% of high schools nationally are charter schools.)

U.S. News uses a three-step process to determine who makes its Best High Schools list: (1) Assess if a school is beating expectations for students in its state, (2) Assess if a school is serving disadvantaged students — and whether those students are outperforming students in the state, and (3) Assess the students’ level of college readiness based on AP and IB results.

The results for urban charter schools are stronger than the results for all charter schools nationally.

Some cities’ charter schools are producing extremely positive results. The most successful urban charter sectors, according to CREDO, include Boston, the Bay Area, Newark, Washington, D.C., Memphis, New York City and New Orleans.

Some are producing negative results. Some of the most unsuccessful urban charter sectors, according to CREDO, include Las Vegas, Fort Worth, El Paso, West Palm Beach and Phoenix.

Stanford researchers found that across all urban regions, black students in poverty who attended charter schools received the equivalent of 59 days of additional learning in math and 44 days of additional learning in reading compared to their peers in traditional public schools.

Hispanic students in poverty experienced the equivalent of 48 days of additional learning in math and 25 days of additional learning in reading in charter schools relative to their peers in traditional public schools. Hispanic students who were classified as English Language Learners experienced the equivalent of 72 days of additional learning in math and 79 days of additional learning in reading in charter schools relative to their peers in traditional public schools.

Research shows that the positive impact of a charter school education grows over time. The Stanford researchers’ urban charter school study found that the longer a student attends a charter school, the more his or her learning progress is amplified.

While some charter schools are helping students learn and make progress, others are hindering students’ performance and progress.

In the 2013-14 school year — the most current year for which data are available — authorizers shut down 3.8% of all charter schools in their portfolios for academic failure, mismanagement, or other causes, according to the National Association of Charter School Authorizers.

Charter schools are expected to live up to the expectations established when they were authorized. If they aren’t succeeding, their authorizer is supposed to shut them down. Eleven states have “automatic closure laws,” under which schools not meeting standards are shut down.

Unfortunately, some failing charter schools — like failing district schools — remain open. A Fordham University study, Are Bad Schools Immortal, found that 72% of low-performing charters remained in operation and remained low performing in five years. The same was true of 80% of district schools.

Nationally, it is important to ensure that students have high-quality options by establishing policies that support the creation of high-quality schools, by opening more high-quality schools, and by closing down schools that don’t meet expectations.
In June 2015, charter support organizations covering 95% of charter school families nationally signed onto a Commitment to Quality, promising to work toward creating more rigorous accountability and quality standards.

1. Quick Answer: Overall, They Perform Well

Julian R. Betts and Y. Emily Tang: A Meta-Analysis of the Literature on the Effect of Charter Schools on Student Achievement, August 2014.
Center for Research on Education Outcomes: National Charter School Study: Executive Summary, 2013

2. Longer Answer: It Depends

Center for Research on Education Outcomes: Urban Charter School Study: Report on 41 Regions, 2015

3. Some Schools and Networks Achieve Strong Results

Christina Clark Tuttle and colleagues: KIPP Middle Schools: Impacts on Achievement and Other Outcomes, February 27, 2013
KIPP: FAQ

4. Some Charter Schools are Winning Accolades

National Center for Education Statistics at the U.S. Department of Education: Number and enrollment of public elementary and secondary schools, by school level, type, and charter and magnet status: Selected years, 1990-91 through 2012-13
US News & World Report, How U.S. News Calculated the 2015 Best High Schools Rankings, May 11, 2015
US News & World Report, Charter Schools Best High Schools, 2015
US News & World Report, National Rankings Best High Schools, 2015

5. City Charters are Strong

Center for Research on Education Outcomes: Urban Charter School Study: Report on 41 Regions, 2015
Center for Research on Education Outcomes: National Charter School Study: Executive Summary, 2013

6. Standout Cities, Both Positive and Negative

Center for Research on Education Outcomes: Urban Charter School Study: Report on 41 Regions, 2015

7. Charters Help Poor and Minority Students

Center for Research on Education Outcomes: p. 17 of Urban Charter School Study: Report on 41 Regions, 2015

8. Students Make More Progress the Longer They Attend

Center for Research on Education Outcomes: p. 26 of Urban Charter School Study: Report on 41 Regions, 2015

9. Some Charters are Mediocre or Failing

National Association of Charter School Authorizers: Infographic
New York Post
Chalkbeat Colorado
NJ.com

10. Great Schools Require Support from Policymakers

National Alliance of Public Charter Schools: National Alliance of Public Charter Schools: National Public Charter Schools Commitment to Quality, June 22, 2015
Separating Fact & Fiction: what you need to know about charter schools
David A. Stuit, Thomas B. Fordham Institute: Are Bad Schools Immortal? The Scarcity of Turnarounds and Shutdowns in Both Charter and District Sectors, December 14, 2010