Charter Schools vs. Public Schools: Methodology Review

Introduction to Charter Schools and the Study

One of the most striking and controversial developments in recent years has been the rapid growth of charter schools in America. Charter schools are publicly funded schools that are released from some of the restrictions governing standard public schools — such as requirements for teacher certification or specific aspects of curriculum management. In exchange for these special provisions, charter schools agree to meet specific goals, often for students whose needs are not met by the standard public educational system. These goals might pertain to the education of the gifted or the disabled, the need to offer higher-level math and science, intensive immersion in the arts, or helping high-risk youth graduate from high school.

While the personalized nature of charter schools has led many politicians and educators to cite them as a solution to the crisis of poorly performing school districts, according to the 2003 Manhattan Institute educational research working paper entitled "Apples to Apples: An Evaluation of Charter Schools Serving General Student Populations," little research had been conducted on charter schools at that time. This is partially due to the idiosyncratic nature of many of these educational facilities. Many are designed to suit the needs of challenging populations — such as special needs students or delinquent youth — or, conversely, the schools selectively recruit the best and brightest for their student bodies. A comparison with public schools within their district is neither fair to the charter school nor to the mainstream public institutions nearby. As nearly a quarter of all charter schools tailor their curricula to specific demographics, useful cross-comparative studies have proved elusive.

The authors — Greene, Foster, and Winters — hoped that deploying a large-scale quantitative approach comparing charter schools with similar demographic populations to their corresponding public school counterparts would offer a sound quantitative perspective on the potential gains charter schools can yield for students. If the charter schools have similar aims to those of nearby, more traditional school districts, the comparison is fair. As the authors explain: "Since the goal of our study is to overcome the problem of differences in student populations, it is particularly important that we remove the influence of student background characteristics to the extent that we can. Excluding targeted charter schools that are unlikely to have a counterpart in the regular public school system [such as science magnet schools or schools for students with special needs] is by far the most important way in which we do this; comparing each charter school to its closest regular public school is another" (Greene, Foster, & Winters, 2003, p. 9).

Study Design and Scope

The number of charter schools is growing, and this growth has been encouraged by the nation's political leaders. Although the comparison between charter and standard public schools may be imperfect, the need to establish some basis of comparison cannot be ignored, state the study authors. At the time of the study, there were 2,700 charter schools within America, with 684,000 children enrolled nationwide (Greene, Foster, & Winters, 2003, p. 1).

The study was conducted over the duration of a single year and involved eleven states: Arizona, California, Florida, Texas, Michigan, Wisconsin, Ohio, Colorado, North Carolina, Minnesota, and Pennsylvania — all of which "had large enough numbers of charter schools to give us a good chance of yielding sufficiently large samples after targeted schools were eliminated." The researchers also included four additional states — Illinois, New York, New Jersey, and Indiana — that "had fewer charter schools but were of particular interest" because of their diverse demographic composition (Greene, Foster, & Winters, 2003, p. 6). However, every state has its own regulations governing how charter schools are approved and which educational requirements may be waived for them (Greene, Foster, & Winters, 2003, pp. 2–3).

Assessment Measures and Key Findings

The quality of the schools under review was assessed solely on the basis of standardized test scores. Test score improvements were measured by comparing the test-case year to both the previous and following school years. It was found that, on average, "charter schools serving the general student population outperformed nearby regular public schools on math tests by 0.08 standard deviations, equivalent to a benefit of 3 percentile points for a student starting at the 50th percentile. These charter schools also outperformed nearby regular public schools on reading tests by 0.04 standard deviations, equal to a benefit of 2 percentile points for a student starting at the 50th percentile" (Greene, Foster, & Winters, 2003, p. 1).

Reference

Greene, Jay P., Greg Foster, & Marcus Winters. (2003, July). Apples to apples: An evaluation of charter schools serving general student populations. Center for Civic Innovation at the Manhattan Institute. Education Working Paper.