How do charter schools impact traditional public schools?

On average, charter schools don't do much for the students who attend them. But how do they impact traditional public schools in their districts? Proponents argue that charters increase the efficiency of public schools via competition while opponents claim they siphon away crucial resources.

Unfortunately, the evidence is just as divided.

Depending on where you look, charter schools have had mixed effects on student achievement at nearby public schools, funding per pupil, and even how public schools allocate their funds. Moreover, the evidence base on the competitive effects of charters tends to be less strong than the research on their direct effects.

Perhaps the most established finding is that charter schools are associated with an increase in school-level racial segregation within a given district. There is evidence to suggest that Black, White, and Latino students all prefer to attend charters at which they're better represented than their local public school. However, these school-level trends may be at least partially offset by a reduction in segregation across districts.

If anything is clear about charter schools, it's that they're a mixed bag.