The What Works Clearinghouse (WWC) Standards Briefs explain the rules the WWC uses to evaluate the quality of studies for practitioners, researchers, and policymakers. Attrition (loss of sample) occurs when individuals initially included in a study are not included in the final study analysis. Attrition is a common issue in education research and…

This monograph looks first at opportunities provided by research in the adult literacy field and then identifies challenges to scientific research and suggests ways to address these challenges so that better evidence can be generated in the future. It has two goals that support the building of a stronger research base for the adult literacy…