Question

No-excuses charter schools in New York City and Boston have been shown to have significant effects on student outcomes. Why can’t this finding be generalized to all charter schools?

Answer 1

"No Excuses" charter schools are those schools that focused intensely on raising the math and literacy scores of their students, who primarily come from low-income and racial minority backgrounds, in a deliberately regimented attempt to narrow the Black–White achievement gap. In these schools principals had management freedom, performance goals are based on measurable metrics, students are rigorously tested, strictly disciplined, and a focus on academic achievement is pervasive. The concept of "No Excuses" charter schools popularized in the year 2003.

The following reasons will help you to understand why we should we wary about generalizing these results to all charter schools:

1) The most rigorous, lottery-based studies of No Excuses charter schools typically focus on specific schools that are located in a single city or belong to single charter-school network, so the findings of any individual study cannot be generalized broadly.

2) Lottery-based studies, of course, cannot be performed at schools without lotteries. No research can make generalizations about students who do not enter a lottery and remain in traditional public schools based on comparisons to students who enter a lottery to enroll in a charter school. In the case of charter schools, it is possible that schools without waiting lists or well-maintained lottery records may produce systematically different achievement results. Thus, the achievement impacts of charter schools with lotteries may not be representative of charter schools more generally.