Can a state’s charter school sector improve over time? Yes, finds this new study of Texas charter schools. Using student data collected from 2001 to 2011, a period of explosive charter school growth in Texas, researchers examined trends in the charter-quality distribution, as measured by value-added results on math and reading test scores. They discovered that in the early- to mid-2000s, charter-sector quality fell considerably short of district quality. But by 2011, the charter-quality distribution improved, converging to virtual parity with district quality. The magnitude of the quality shift in Texas charters, note the researchers, is large and substantial (0.11 and 0.20 standard deviations in math and reading, respectively). What is the source of the quality improvement? The main reason is strikingly straightforward: Lower value-added charter schools tended to shutter over time, while higher value-added schools entered the sector. Meanwhile, schools that remained open throughout the whole period also demonstrated improvement over time. The researchers next peel back the layers of the sector-improvement onion. They discover three contributing factors: First, Texas charters have attracted students of higher achievement levels (i.e., positive “selection”), possibly leading to positive peer effects captured in the value-added results. Second, charters have experienced less student turnover as the sector has matured. Third, the analysts find evidence that the growth of schools classified as “no-excuses” charters has propelled overall sector quality. The policy takeaways for Ohio are twofold: One, it takes time for high-quality schools to edge low-quality ones out of the school marketplace. (And authorizers can also expedite the departure of weak schools as well.) Secondly, policymakers (and philanthropists) must direct more resources to help high value-added charters grow, replicate, and expand as quickly as possible. It doesn’t take an accounting degree to tell us that, when the high-performers outnumber the low-performers, overall quality improves. Let’s hope the Buckeye State is up to the task.
Source: Patrick L. Baude, Marcus Casey, Eric A. Hanushek, and Steven G. Rivkin, The Evolution of Charter Schools Quality (Boston, MA: National Bureau of Economic Research, November 2014).
