Many teacher education researchers have expressed concerns about the lack of rigorous impact evaluations of teacher preparation practices. I summarize these various concerns as they relate to issues of internal validity, measurement, and external validity. I then assess the prevalence of these issues by reviewing 166 impact evaluations of teacher…

This review describes a meta-analysis of findings from 50 controlled evaluations of intelligent computer tutoring systems. The median effect of intelligent tutoring in the 50 evaluations was to raise test scores 0.66 standard deviations over conventional levels, or from the 50th to the 75th percentile. However, the amount of improvement found in…

The major theme is that better and more productive studies could emerge if media research would move out of its traditional either-internal- or-external validity conflict. (Author/MV)

This article analyzes 41 studies that evaluated K-12 parent involvement programs in order to assess claims that such programs are an effective means of improving student learning. It examines the characteristics of the parent involvement programs, as well as the research design, data, and analytical techniques used in program evaluation. Our…