This study investigated the effectiveness of a standard protocol Tier 2 reading intervention among third and fifth grade students and the methodologies used to determine the intervention's effectiveness. Several confounding covariates were observed as a result of utilizing eligibility criteria for assignment to the Tier 2 intervention condition.…

A latent trait model, the Rasch, was fitted to a criterion-referenced test. Approximately 90 percent of the items fit the model. Those items which fit the model were then calibrated. Based on the item calibration, individual ability estimates and the standard errors of those estimates were calculated. Using the ability estimates, it was possible,…

In this study we test the performance of some nonexperimental estimators of impacts applied to an educational intervention--reduction in class size--where achievement test scores were the outcome. We compare the nonexperimental estimates of the impacts to "true impact" estimates provided by a random-assignment design used to assess the…