An effect size of about 0.70 (or 0.40-0.70) is often claimed for the efficacy of formative assessment, but is not supported by the existing research base. More than 300 studies that appeared to address the efficacy of formative assessment in grades K-12 were reviewed. Many of the studies had severely flawed research designs yielding…

In this paper, tables for the appropriate sample sizes are presented and discussed in the context that the determination of the effect size must precede the determination of the sample size. (Author/PN)

Speculation about the state of research if metanalysis is pushed to its logical extreme (if at least 1 metanalysis had been conducted on every independent, dependent, and mediating variable for which at least 2 independent effect sizes could be computed) yields 10 effects that could be expected. (SLD)

Some methodological issues in the study of levels of knowledge are reviewed, and needs for further research are explored, drawing on an analysis of 12 studies reported since the late 1970s. In the 12 studies, 16 quantitative experiments were conducted. These were assessed for internal and external validity. Analysis revealed some shortcomings in…

Reports on a study by Henry Becker that surveyed the research comparing the achievement of students using computer to those using traditional methods of instruction. Problems with many earlier studies are described, best-evidence synthesis is explained, effect size is examined, and implications for future research are suggested. (LRW)