California charter schools are significantly contributing to closing the performance gap between low-income and affluent communities, according to a report from the California Charter Schools Association (CCSA). The inaugural Portrait of the Movement report reviews the academic performance of charter schools across the state, details their strengths and weaknesses, and provides a framework of minimum performance criteria to press for greater accountability of low-performing charter schools.
The report includes performance data for 720 charter schools compared against 7,454 non-charter schools. The study indicates high-achieving charter schools serve a disproportionate number of students from low-income populations than traditional public schools in the state.
According to the report, 42.2 percent of low-income charter school students attend schools in the top 10th percentile of California schools, compared to just 10.6 percent of low-income students attending non-charter schools in the top 10th percentile. That gap appears particularly significant considering the percentage of low-income students attending schools in the bottom 10th percentile are relatively equal between charter schools (9.7 percent of low-income students) and non-charters (11.3 percent).
In its analysis of the data, the CCSA believes charter schools “serving low-income populations are generating significantly better academic results than traditional public schools serving the same populations, thus demonstrating that charter schools are weakening the link between poverty and underperformance that is so prevalent in the traditional system.”
Part of the reason for this is the impact of family income on charter schools’ performance is four times less than the impact of family income on the performance of non-charter schools, according to the CCSA.
The report examines school performance in part by using the Similar Students Measure (SSM), a metric developed by CCSA in 2008 and vetted by an advisory panel of external research and evaluation experts. Using public data, the SSM provides an approximation of the added value a school provides to its students, allowing researchers to identify schools that significantly exceed or underperform a prediction based on their students’ background.
According to the report, charter schools (16 percent) are four times as likely as non-charters (3.9 percent) to be in the top 5 percent of California schools that exceed predicted performance. In addition, more than twice as many students are served by charter schools performing above their prediction than those underperforming, according to the CCSA.
While the state’s charter schools appear to be exceeding at the top end of public education, the report also indicates charters are more concentrated than non-charters among underperforming schools. In fact, California charter schools (11.5 percent) are more than twice as likely to be among the state’s bottom 5 percent of schools compared to non-charters (4.4 percent).
“The concentration of charter schools in the bottom 5th and 10th percentiles gives us reason to look more deeply at their academic records and ensure that appropriate accountability is upheld,” officials wrote in their analysis.
The good news for the state’s charter school movement is trending data indicates there is some evidence the concentration of over-performing charter schools is increasing, while the concentration of underperforming charters is decreasing.
Between 2008 and 2010, the concentration of charters in the bottom 5th percentile decreased from 16 percent to 11.5 percent, while the concentration of charters in the top 5th percentile increased from 14.8 percent to 16 percent.
“While these data constitute a small change, this is evidence of a promising trend that we will continue to monitor and analyze more deeply,” officials wrote.
“Charters have built tremendous momentum during the past decade, especially in California, but growth alone is not enough,” said Jed Wallace, CCSA president and CEO. “This report shows that a strikingly large number of California’s charter schools are among the very best public schools in the state, and that charters are serving low-income students more effectively than traditional public schools.”
