"Attrition" is the loss of sample during the course of a study. It occurs when individuals initially randomly assigned in a study are not included when researchers examine the outcome of interest. Attrition is a common issue in education research, and it occurs for many reasons. The What Works Clearinghouse (WWC) is an initiative of the…

Professional development designed to integrate key features of research-based professional learning has positive and significant effects on teacher practice and student achievement in mathematics when implemented in schools that meet specified technology-readiness criteria. Key features of research-based professional learning include intensive…

Research methods are tools that can be variously applied - depending on the stage of knowledge in a particular area, the type of research question being asked, and the context of the research. The field of program evaluation, critical for social policy development, often has not adequately embraced the full range of methodological tools needed to…