• Choose a category
• All
• Classic-Fiction

Single-Point-in-Time Studies

The most comprehensive single-point-in-time study of charter schools was conducted by Harvard University economist Caroline Hoxby.8 She analyzed data from 99 percent of the nation’s charter schools. Hoxby’s study is a straightforward comparison of achievement rather than achievement gains, but it has the huge advantage of including data for essentially all the charter schools in the nation and nearby traditional public schools.

Using state-mandated test data, Hoxby found:

Compared to students in the matched public school, charter students are 5.2 percent more likely to be proficient in reading and 3.2 percent more likely to be proficient in math on their state’s exams. Charter schools that have been in operation longer have a greater proficiency advantage over the matched public schools. For example, in reading, the advantage is 2.5 percent for a charter school that has been operating 1 to 4 years, 5.2 percent for a school operating 5 to 8 years, and 10.1 percent for a school operating 9 to 11 years.9

Hoxby found the largest differences in proficiency levels in states where charter schools were most common. For example, compared to students attending matched traditional public schools, Alaska’s charter students were about 20 percent more likely to be proficient in reading and math, Arizona’s about 10 percent more likely to be proficient in both disciplines, and California’s 9 percent more likely to be proficient in reading and 5 percent more likely to be proficient in math.10

Hoxby’s results suggest that poor and Hispanic students performed well in charter schools and show that they accounted for a higher percentage of charter than of traditional public school enrollments. Another important finding of Hoxby’s study is that charter school students were “more likely to have a proficiency advantage if their state has a strong charter school law that gives the schools autonomy and that ensures that charter schools get a substantial fraction of the total per-pupil funding of traditional public schools.”11

Hoxby found that in large urban school districts with high levels of choice, charter schools were 35 percent more likely to have curricula with rigorous core requirements in English, mathematics, social studies, science, and foreign language.12 Schools of choice in these districts also demonstrated more structured classrooms, heightened attention to academic discipline, and greater use of student standardized test results to evaluate administrative performance. Research shows these conditions yield higher achievement.13

Finally, Hoxby also reported that charter school students are more likely to have relatively higher achievement than traditional school students if their state enacted a charter law early. Top-performing states for charter schools, with early charter school law enactment dates, are Arizona, 1994; California, 1992; Colorado, 1993; the District of Columbia, 1996; Hawaii, 1994; Illinois, 1996; Louisiana, 1995; and Massachusetts, 1993. On average, states with charter school laws enacted them in 1996, but 10 states have no charter law yet. States that enacted their laws early tend to be more likely to provide more adequate funding, more autonomy, multiple chartering authorities, and other benefits to charter schools, which appear to be the reasons their charter schools achieve better outcomes than traditional schools in their states .14

Thus, the largest single-point-in-time study ever carried out suggests that charter schools exceeded traditional schools in achievement, that poor and Hispanic students do especially well in them, and that outcomes improve as charter schools gain experience and are given more autonomy and funding levels closer to those of traditional public schools.

Two other more recent single-point-in-time studies of charter schools appeared to contradict Hoxby’s findings. The first, by the American Federation of Teachers—the nation’s second-largest teachers’ union—received front-page coverage in