I define a treatment effect in terms of a comparison of outcomes and provide a typology of all possible comparisons that can be used to estimate treatment effects, including comparisons that are relatively unknown in both the literature and practice. I then assess the relative merit, worth, and value of all possible comparisons based on the…

A large body of literature documents the central importance of fidelity of program implementation in creating an internally valid research design and considering such fidelity in judgments of research quality. The What Works Clearinghouse (WWC) provides web-based summary ratings of educational innovations and is the only rating group that is…

The present meta-analysis examines the effect of grade retention on academic outcomes and investigates systemic sources of variability in effect sizes. Using multilevel modeling (MLM), the authors investigate characteristics of 207 effect sizes across 22 studies published between 1990 and 2007 at two levels: the study (between) and individual…

Involvement in student affairs professional development was investigated using McClusky's (1963) Power Load Margin (PLM) theory from the adult education field. The PLM theory is a framework for identifying sources of stress (load) and power in one's life; the amount of power available to handle stress is called margin in life (MIL). This study…