Four years after a study by Stanford’s Center for Research on Education Outcomes found the academic performance of charter school students to be lagging behind that of their public school peers, an updated version of the study has shown signs of incremental improvement in charter schools.
The original 2009 CREDO report, titled “Multiple Choice,” looked at charter schools in 16 states. The 2013 study encompassed 10 more states, including Indiana and Utah, and — by covering 79 percent of tested public school students and 95 percent of U.S. charter school students — constituted one of the largest studies on charter schools to date.
To compare charter and public schools, CREDO assigned each charter school student a “virtual twin”: a traditional public school student with the same socioeconomic background, ethnicity, school district based on residence and starting standardized test scores. CREDO then tracked the students’ scores and academic growth in reading and math over time.
The study found that charter school students outperformed peers from traditional public schools in math and reading in some states, such as Rhode Island and Tennessee, but lagged behind in others, like Nevada. Overall, however, charter schools have improved on average since 2009.
“Now the average charter school student gains about eight days in learning in reading over and above what the traditional public school counterpart gets,” said Devora Davis, CREDO’s research manager. “They have about the same learning gains in math.”
By contrast, the 2009 study found charter students to be behind their public school peers by seven and 22 days of learning in reading and math respectively. The 2013 study also found a greater number of charter schools outperforming public schools.
“In 2009…17 percent of charter schools were outperforming their traditional public schools in math, and it was about 19 percent in reading. That wasn’t something we had ready to publish at that time, but we did that subsequent work,” Davis said. “[Today] 29 percent of the charter schools in math and 25 percent of the charter schools in reading have better learning gains than the local alternative.”
The study also found that the majority of charter school students are now economically disadvantaged, suggesting that the alternative system might now provide better education for less privileged students. In the original 16 states surveyed, the proportion of charter students who are economically disadvantaged has risen from 49 percent to 61 percent.
According to the CREDO report, charter schools have seen an 80 percent increase in students nationally since 2009. The National Alliance for Public Charter Schools estimated that in the 2012-2013 school year over 6,000 U.S. charter schools served about 2.3 million students.
Davis pointed to charter schools’ autonomy as a potential factor in their success, noting that their ability to operate privately while backed by public funding allows more flexibility in both their academic curricula and their budget allocations, and drew attention to the ability to close underperforming charter schools.
“We did see that when they closed underperforming schools, they were more likely to have better results,” Davis said. “Some of the slow and steady progress I was talking about…is because of the closure of underperformers.”
Although the study did not take charter schools’ different curricula into account, Davis expressed hope that the study would encourage further improvement as charter schools imitate peers in states with higher learning gains.
“We now have enough data from enough states to see that there are some states that are starting up charter schools that have good performance right out of the gate,” Davis said. “States that aren’t doing as well might be able to look at what other states are doing that are getting better results and to teach those learning.”