Evaluators of education interventions are increasingly designing studies to detect impacts much smaller than the 0.20 standard deviations that Cohen characterized as "small." While the need to detect smaller impacts is based on compelling arguments that such impacts are substantively meaningful, the drive to detect smaller impacts may…

Evaluators of education interventions increasingly need to design studies to detect impacts much smaller than the 0.20 standard deviations that Cohen (1988) characterized as "small." For example, an evaluation of Response to Intervention from the Institute of Education Sciences (IES) detected impacts ranging from 0.13 to 0.17 standard…

Evaluators of education interventions are increasingly designing studies to detect impacts much smaller than the 0.20 standard deviations that Cohen (1988) characterized as "small." While the need to detect smaller impacts is based on compelling arguments that such impacts are substantively meaningful, the drive to detect smaller impacts…

The regression discontinuity design (RDD) has the potential to yield findings with causal validity approaching that of the randomized controlled trial (RCT). However, Schochet (2008a) estimated that, on average, an RDD study of an education intervention would need to include three to four times as many schools or students as an RCT to produce…

Regression discontinuity designs (RDDs) are considered to be one of the strongest nonexperimental designs available for the purpose of identifying the effects of an intervention. RDD can be used in situations in which assignment to a treatment group is based on a cutoff value on a continuous assignment variable. The impact of the intervention is…

This report lays out the design for the Evaluation of Reading Comprehension Interventions, which is assessing supplemental reading comprehension programs for fifth-grade students in Title I schools. The key design parameters are described. The report itself provides the rationale for these decisions and discusses design and measurement issues,…