Stanford study finds Tennessee public charter school students outperforming traditional students more than any southern state

A new study by Stanford's Center for Research on Education Outcomes (CREDO) found public charter school students in Tennessee are not only making more average progress than their traditional public-school peers, but also outperforming them at greater rates than other southern states.CREDO released the study on Tuesday as a continuation of public charter school studies in 2013 and 2009.Nationwide CREDO found the benefit of attending public charter schools during the latest study period amounted to an additional 16 days of learning in reading and an additional 6 days of learning in math.That variance was even higher in Tennessee, with public charter school students showing an additional 33 days of learning in reading and nearly 39 days in math. No other southern state had public charter school students reaching 25 additional days of learning in either subject.The CREDO study also found no evidence that public charter schools in Tennessee are “cherry picking” the highest performing students as some charter opponents claim.The study compared students who initially enrolled in a traditional public school and took at least one achievement test before transferring to a public charter school, to their peers who enrolled in the traditional public school. CREDO found the share of students entering Tennessee public charter schools from the highest levels of achievement was 11 percent lower and the share from the lowest levels of achievement nearly 5 percent higher.For the study, CREDO evaluated data from 81 percent of tested public-school students in the United States from 2014 to 2019. That data helped compare 1.8 million public charter school students with a “virtual twin” from a traditional public school with similar test scores, traits, and who were enrolled in schools the charter students would have likely attended.“In theory, this virtual twin would only differ from the charter student in that the charter student attended a charter school and the twin attended a TPS (traditional public school),” wrote CREDO in the report.Tennessee public charter schools also showed positive gains on school-level performance in the study.To compare school-level performance, CREDO computed each public charter school’s average impact on student learning over the two most recent growth periods (2017 and 2018).The study found more Tennessee public charter schools showing stronger growth compared to traditional public schools in both subjects than weaker growth.