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…

The report of the National Council of Teachers of English Task Force on Study of Class Size and Workload in Secondary English Instruction takes the position that class size should be studied by itself and also in conjunction with other variables. It also identifies subject matter and instructional design as types of variables combining with class…

Research on the relationship of class size to academic achievement is being used by administrators, parents, teachers, and politicians. Unfortunately, many questions are being raised on the methodology, results, and conclusions of the research studies. (FG)

Reviews research into class size effects from a methodological viewpoint, concentrating on various strengths and weaknesses of randomized controlled trials (RCT) and observational studies. Discusses population definitions, causation, and generally sets out criteria for valid inferences from such studies. Illustrates with new findings from data in…

Discusses research (Tennessee Study of Class Size) that determined the effects of smaller class size in the earliest grades on short- and long-term pupil performance. The 4-year study assessed the performance of over 6,500 students who attended K-3 classrooms having differing numbers of students and found evidence of short- and long-term benefits…