During drug development, a biomarker is sometimes identified as separating a patient population into those with more and those with less benefit from evaluated treatments. Consequently, later studies might be targeted, while earlier ones are performed in mixed patient populations. This poses a challenge in evidence synthesis, especially if only…

This paper presents a critical analysis, from the point of view of a statistician, of the methodology used by Hattie in "Visible Learning," and explains why it must absolutely be called pseudoscience. We first discuss what appears to be the intentions of Hattie's approach. Then we describe the major mistakes in "Visible…

A review of 13 years of research into antecedents of university students' grade point average (GPA) scores generated the following: a comprehensive, conceptual map of known correlates of tertiary GPA; assessment of the magnitude of average, weighted correlations with GPA; and tests of multivariate models of GPA correlates within and across…

The current review addresses the validity of published meta-analyses in education that determines the credibility and generalizability of study findings using a total of 56 meta-analyses published in education in the 2000s. Our objectives were to evaluate the current meta-analytic practices in education, identify methodological strengths and…

The authors have over the years tried to revise meta-analysis because it's basic premise is to add apples and oranges together and analyze. In other words, various data on the same subject are chosen using different samples, research strategies, and number properties. The findings are then homogenized and a statistical analysis is used (Snell, J.…

Meta-analytic reliability generalizations (RGs) are limited by the scarcity of reliability reporting in primary articles, and currently, RG investigators lack a method to quantify the impact of such nonreporting. This article introduces a stepwise procedure to address this challenge. First, the authors introduce a formula that allows researchers…

Multivocal literatures are comprised of all accessible writings on a common topic and embody the views of diverse authors. The exploratory case study method is proposed as a way to ensure rigor in reviews of such literatures because it addresses problems associated with the selective use of data. (SLD)

The six articles of this issue discuss the place of meta-analysis in the health professions and present two state-of-the-art meta-analyses using a variety of innovative methodologies, statistics, and secondary analytic procedures. A survey conducted for this issue and its sequel explores interventions to facilitate meta-analysis. (SLD)