Evaluations of educational programs or interventions are typically conducted in nonrandomly selected samples of schools or districts. Recent research has shown that nonrandom site selection can yield biased impact estimates. To estimate the external validity bias from nonrandom site selection, we combine lists of school districts that were…

Extensive teacher mobility can undermine policy efforts to develop a high-quality workforce. In response, policymakers have increasingly championed financial incentives to retain teachers. In 2006, the Denver Public Schools adopted an alternative teacher compensation reform, the Professional Compensation System for Teachers ("ProComp").…

This case history of the Colorado Study of Learning Disabilities illustrates a variety of functions an evaluation study may serve for policy shapers at the state level. The impact of the initial evaluation is followed over two years, focusing on its use by influential participants in Colorado's special education policy-shaping community. (BW)