Skeptics of the KIPP (Knowledge Is Power Program) charter school network argue that these schools rely on selective admission, attrition, and replacement of students to produce positive achievement results. We investigate this using data covering 19 KIPP middle schools. On average, KIPP schools admit students disadvantaged in ways similar to other…

Randomized controlled trials (RCTs) are widely considered to be the gold standard in evaluating the impacts of a social program. When an RCT is infeasible, researchers often estimate program impacts by comparing outcomes of program participants with those of a nonexperimental comparison group, adjusting for observable differences between the two…