This paper introduces an empirical strategy to estimate dynamic treatment effects in randomized trials that provide treatment in multiple stages and in which various noncompliance problems arise such as attrition and selective transitions between treatment and control groups. Our approach is applied to the highly influential four year randomized…

Education lacks scientifically sound studies, whether researchers are examining promotion versus retention, class-size effects, or private voucher schemes. American public schools have educated the world's most productive work force, test scores are rising, and more kids graduate than formerly. Educators should demand compelling evidence before…