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Benefits for elementary school reading and middle school math. In one of Betts and Tang’s (2008) major conclusions, a majority of studies showed that charter schools performed better than traditional public school students in elementary school reading and middle school math. Similar results were found in the CREDO study. Where gains were evident, CREDO found, the success was generally in reading at the elementary school level and in reading and math at the middle school level.
Drawbacks in high school. Conversely, Betts and Tang found that charter schools underperform in math and reading at the high school level. The CREDO study also found no evidence of a net gain during high school. In addition, students in “multi-level” (i.e., K–8 or 7–12) charter schools underperformed counterparts from traditional public schools in both reading and math.
Some charters do better; the majority do the same or worse. CREDO also moved beyond individual student performance to examine the overall performance of charter schools across multiple subject areas. They found that while some charter schools do better than the traditional public schools that fed them, the majority do the same or worse. Almost one-fifth of charters (17 percent) performed significantly better (at the 95 percent confidence level) than the traditional public school. However, an even larger group of charters (37 percent) performed significantly worse in terms of reading and math. The remainder (46 percent) did not do significantly better or worse.
Results vary from state to state. Most studies found that performance varied based on students’ location. It is noteworthy to compare state-by-state achievement with data on public school authorizers, though no study has directly analyzed the two.
Conflicting results for specific groups. Few multi-site or multi-state studies examine how specific racial/ethnic groups perform in charter schools, and those that exist often show conflicting results.
Given the research base, any explanation of why some charters succeed and others don’t is speculative. A possible answer is that successful charter schools use strategies that research has proven are often effective—smaller schools, smaller class size, more school time, and greater parent involvement. It is not known whether hallmarks of charter schools—such as a lack of collective bargaining or greater autonomy—affect achievement. It is an area that should be researched.
Frederick Hess, education policy director at the American Enterprise Institute and a strong advocate for charter schools, notes that many charter sponsors rely on dedicated staff and a “missionary zeal” to succeed (Hess 2009). “The most successful charter ventures to date have been boutique-style operations that are extraordinarily reliant on talent and passion, philanthropic funding, and exhausting work schedules,” (Higgins and Hess 2009). Yet, he notes, the “means of bringing them to scale have been elusive.”
Charter schools across the nation
While charter school students enrolled just 3 percent of all public school students in 2008, the number of students (and schools) has risen dramatically in the past decade. In 1999, there were 1,542 charter schools with 349,642 students. By 2008, there were 4,618 charter schools with 1,407,817 students (National Alliance for Public Charter Schools 2009b).
As the enrollment numbers have grown, some in the education community have become concerned. The RAND Corporation’s study (Zimmer et al 2009) attempted to evaluate whether charter schools are “skimming” the best students from local traditional public schools or re-segregating urban schools. RAND analyzed the academic achievement and demographic characteristics of students transferring into charter schools and found:
Charter schools generally are not drawing the best students away from local traditional public schools. For example, previous test scores for students transferring into charter schools were near or below the averages for every location in the study. Only among white students did researchers find slightly higher test scores among those moving to charter schools.
The racial composition of charter schools was similar to that of the traditional public schools the students previously attended.
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