Charter Schools’ Effectiveness, Mechanisms, and Competitive Influence

Across the United States, charter schools—publicly funded and regulated, but privately run schools—appear to perform, on average, at about the same level as their district counterparts. The broadest studies of charter school effectiveness use observational methods, which may not fully account for selection of students into charter schools. However, this finding is confirmed by lottery-based evidence from a few broad samples that again presents a varied picture of charter impact and little average difference across sectors. Underlying the similarity in performance across sectors is one of the most consistent findings from both observational and lottery-based evidence of charter schools’ impact on student achievement: Charters located in urban areas boost student test scores, particularly for Black, Latinx, and students from lower-income households. The test score gains appear to be largest in urban charters that employ “No Excuses” practices. Attending some urban charter schools also increases college enrollment and voting and reduces risky behavior. However, evidence on such long-term outcomes is limited to a few samples, and evidence on college graduation and adult earnings is even rarer, making it difficult to draw conclusions beyond test scores about the overall effectiveness of the charter sector. Research on the mechanisms underlying charter successes, when they occur, is growing. No Excuses charter schools—which employ high expectations, strict disciplinary codes, and intense academic focus—generate consistent test score gains, but their controversial disciplinary practices are not necessarily a condition for academic success. Charter school teachers tend to be less qualified and more likely to leave the profession than traditional public school teachers, though the impact of these challenges for the labor market is understudied. Similarly, the influence of charter authorizers and related accountability structures is limited and would benefit from examination using more rigorous methodologies. The competitive impact of charter schools on traditional public schools typically suggests a small, beneficial influence on neighboring schools’ student achievement, though there is variation across contexts. Additionally, while some local analyses suggest charters reduce funding in nearby districts, at least in the short term, a larger scale study finds charter entry generates more revenue per pupil for district schools. There is competing evidence on charters’ contribution to school racial segregation, and little evidence on the impact of newer, intentionally diverse school models. In all, more research, in more contexts, is needed to further understand where, for whom, and why charters are most effective.