Charter school effects remain uncertain. Small lottery studies on high-performing charters produce impressive results, but large observational studies on the full range of charter schools are less encouraging. To make matters worse, these observational studies that aim for representativeness are based on only switchers, a small and unrepresentative population, arguably defeating the purpose of this design. In the first study of charter school effects on the full range of charter school students in North Carolina, we find that, in general, charter school performance has improved over time, although often it continues to remain lower than traditional public school achievement. However, we find some evidence suggesting that black and economically disadvantaged students experience slightly more achievement growth in charter schools, particularly in reading, than do students who are white and not economically disadvantaged.

中文翻译：

---

评估北卡罗来纳州特许学校的成就增长：弱势学生、留守者和转换者之间的差异化影响

特许学校的影响仍然不确定。对高绩效特许学校的小型抽签研究产生了令人印象深刻的结果，但对所有特许学校的大型观察性研究并不那么令人鼓舞。更糟糕的是，这些以代表性为目标的观察性研究仅基于转换者，这是一个小而无代表性的人群，可以说违背了这种设计的目的。在第一次关于特许学校对北卡罗来纳州特许学校学生的影响的研究中，我们发现，总的来说，特许学校的表现随着时间的推移而有所改善，尽管它通常仍然低于传统的公立学校成绩。然而，我们发现一些证据表明黑人和经济上处于不利地位的学生在特许学校的成就增长略多，