Do charter schools increase student achievement?
In some cases, but not on average.
Charter schools generate interest among parents by touting innovative teaching models and the benefits of competition. But the evidence suggests they are not a panacea: on average, charter schools in the U.S. tend to perform at the same level as their district counterparts.
Instead, the way to think about charters schools is that they work best in certain contexts. For example, charters located in urban areas appear to boost test scores, particularly for lower-income Black and Latino students. These achievement gains are largest at "No Excuses" schools which have an intense academic focus and especially high standards. "No Excuses" schools are controversial for their strict disciplinary codes, but research suggests that they could maintain their performance edge even without employing them.
All in all, charter schools appear to increase achievement only among some students. But a comprehensive evaluation of charters would also need to incorporate their effects on traditional public schools in the same district.