It seems logical that motivated families leaving traditional public schools in favor of charter schools or private schools would harm the traditional school system. But that’s not what the research says, at least so far.

The graph below comes from a new Mathematica brief looking at studies that measured the causal effect of school choice on traditional public schools. As the graph shows, 10 studies that met Mathematica’s evidence bar found no effects of charter schools on traditional schools, nine found positive effects, two studies reported mixed results, and three found negative effects.

The studies included here were mainly looking at the early-stage phase-in of charter schools in various districts, and it’s possible that the balance might tilt away from charters as they grow their market share. But the evidence thus far suggests that charters either have no effect or perhaps even a slightly positive effect on traditional public schools.

In a separate brief, Mathematica looked at the effects of school choice on racial and economic integration. They concluded, “Among the studies with charter schools, 2 studies found that charter schools increased integration, 5 found no effect on integration, and 3 found that they decreased integration. Most studies we reviewed that found effects on integration tended to report small effects.”

–Guest post by Chad Aldeman