Charter schools have been increasingly advocated as a means for supporting innovation in
public schools, and they are a growing element of the school sector. According to the National Alliance
for Public Charter schools, by 2007, 40 states and the District of Columbia had created 4,046 charter
schools serving 1.1 million students across the nation. Four hundred charter schools opened in that
year, representing a 12 percent increase from the previous year. Increases have continued in the
Some successful charters have been founded and have received significant attention.
However, many others have been unsuccessful. Overall, research on the effectiveness of charter
schools has been decidedly mixed. As Scott Imberman of the University of Maryland found in his
review of evidence on outcomes in charter schools:
(S)ome researchers find insignificant or negative impacts of attending a charter school
(Hanushek, Kain, Rivkin and Branch, 2007; Bifulco and Ladd, 2006; Sass, 2006; Zimmerand
Buddin, 2003), while others find positive impacts (Booker, Gilpatric, Gronberg and Jansen,
2007; Hoxby and Rockoff, 2004; Solmon and Goldschmidt, 2004; Solmon, Paark and Garcia,
2001). Thus, we might conclude from these studies that the effect of charter schools on
academic performance is, at best, unclear.1
A recent large-scale study from the Center for Research on Education Outcomes at Stanford University, examining longitudinal student data in 16 states, found that only 17 percent of charter schools produced academic gains that were significantly better than traditional public schools, while students in 37 percent of charter schools performed worse than their traditional public school counterparts. In 46 percent of charter schools, there was no significant difference between their students’ achievement gains and those of their demographically similar peers in district-run public schools.2
Other reviews of research report similarly mixed findings,3 noting that charters have had widely varying outcomes across different contexts. Where charters have been poorly regulated, results for students have typically been negative. For example, in Ohio, where an unregulated market strategy created a huge range of for-profit and nonprofit providers with few public safeguards, charter school students have been found to achieve at consistently lower levels than their demographically similar public school counterparts.4 Students in charters in largely unregulated Arizona and Washington, DC have also been found to achieve at levels significantly below those of their similar peers in public schools.5 In Minneapolis, Minnesota, where charters have proliferated, a recent study found that, on average, they produce significantly lower achievement relative to district public schools serving similar students.6
A recent study in California found charter outcomes varied by type, with students in middle school charters scoring above and elementary charters scoring below their demographically similar counterparts. High school charters did better in English language arts and worse in mathematics.7 In addition, students did particularly poorly in charters providing most of their instruction through home schooling, independent study, or distance learning.
A recent evaluation of Chicago’s Renaissance 2010 initiative – which replaced a group of lowperforming schools with charters and other schools of choice run by entrepreneurs and the district -- found that the achievement of students in the new schools was no different from that of a matched comparison group of students in the old schools they had left, and both groups continued to be very low-performing.8
Some studies have found that charters have increased segregation in public schools, both racially and in terms of academic programs. For example, a Texas study found that the majority of white, Anglo students in the state’s charters were in academically oriented schools, while most minority students were in vocational charters.9
In sum, while charters may be one strategy among many, to spark innovation and improvement in public schools, they are not a silver bullet. Investments that improve instruction, curriculum quality and access, school management, and student supports are needed to produce educational quality, regardless of school governance or sector.
1 Imberman, S. (2007). Achievement and Behavior in Charter Schools: Drawing a More Complete
Picture Occasional Paper 142. Occasional Papers. New York, National Center for the Study of
Privatizations in Education: 48.
2 CREDO (2009). Multiple choice: Charter school performance in 16 states. Stanford, CA: CREDO,
3 Miron, G. and C. Nelson (2001). Student Achievement in Charter Schools: What We Know and Why
We Know So Little. Occasional Paper No. 41. New York: Teachers College, Columbia University.
National Center for the Study of Privatization in Education: 36; American Federation of Teachers
(2002). Do Charter Schools Measure Up? The Charter School Experiment After 10 Years. Washington,
DC: American Federation of Teachers.
4 Miron, G., Coryn, C. et al. (2007). Evaluating the Impact of Charter Schools on Student Achievement:
A Longitudinal Look at the Great Lakes States. Education Policy Research Unit. Tempe Education
Policy Research Unit, Arizona State and Education and the Public Interest Center, University of
Colorado: 20. Messina, I. (2005). "State to Review Charter School Concerns." Retrieved November
12, 2007, 2007, from http://oh.aft.org/index.cfm?action=article&articleID=d2bd2915-42dd-487c-
5 Carnoy, M., Jacobsen, R., Mishel, L., and Rothstein, R. (2005). The charter school dust-up: Examining
the evidence on enrollment and achievement. Washington, DC: Economic Policy Institute.
6 Institute on Race and Poverty (2008). Failed Promises: Assessing Charter Schools in the Twin Cities.
Minneapolis: University of Minnesota, Institute on Race and Poverty.
7 EdSource (2008). California’s Charter Schools: 2008 Performance Update. Palo Alto, CA: EdSource.
8 Young, V.M., Humphrey, D.C., Wang, H., Bosetti, K.R., Cassidy, L., Wechsler, M.E., Rivera, E., Murray,
S., & Schanzenbach, D.W. (2009). Renaissance Schools Fund-supported schools: Early Outcomes,
challenges, and opportunities. Menlo Park, CA: Stanford Research International and Chicago:
Consortium on Chicago School Research. Retrieved on 5/21/09 from http://ccsr.uchicago.edu/publications/RSF%20FINAL%20April%2015.pdf
9 Wamba, N. G. and C. Ascher (2003). An Examination of Charter School Equity. Education and Urban
Society 35(4): 462-476.