The vast amount of research conducted on student persistence over the past thirty years is indicative of the continuing and evolving interest in retention of students. Framed through multiple perspectives, this retention research is driven by the fact that more students leave institutions without graduating, year after year. Much more than an…

This study examines the performance of a new method for assessing and characterizing dimensionality in test data using the NOHARM model, and comparing it with DETECT. Dimensionality assessment is carried out using two goodness-of-fit statistics that are compared to reference X[2] distributions. A Monte Carlo study is used with item parameters…

In the social sciences, evaluating the effectiveness of a program or intervention often leads researchers to draw causal inferences from observational research designs. Bias in estimated causal effects becomes an obvious problem in such settings. This article presents the Heckman Model as an approach sometimes applied to observational data for the…