This paper, originally published in Evaluation Review, provides researchers with new information about the values of the key design parameters needed for planning randomized controlled trial evaluations of interventions in community colleges.
Using an alternative to classical statistics, this paper reanalyzes results from three published studies of interventions to increase employment and reduce welfare dependency. The analysis formally incorporates prior beliefs about the interventions, characterizing the results in terms of the distribution of possible effects, and generally confirms the earlier published findings.
This paper provides practical guidance for researchers who are designing and analyzing studies that randomize schools — which comprise three levels of clustering (students in classrooms in schools) — to measure intervention effects on student academic outcomes when information on the middle level (classrooms) is missing.
Methodological Lessons from an Evaluation of Accelerated Schools