Heterogeneity is commonplace in meta-analysis. When heterogeneity is found, researchers often aim to identify predictors that account for at least part of such heterogeneity by using mixed-effects meta-regression models. Another potentially relevant goal is to focus on the amount of heterogeneity as a function of one or more predictors, but this…

The meta-analytic random effects model assumes that the variability in effect size estimates drawn from a set of studies can be decomposed into two parts: heterogeneity due to random population effects and sampling variance. In this context, the usual goal is to estimate the central tendency and the amount of heterogeneity in the population effect…

In a response to comments by P. T. Costa, Jr., and R. R. McCrae on the current authors' original article, the authors show that Costa and McCrae's writings on personality suggest a belief in immutability of personality traits. The authors agree with Costa and McCrae that new personality trait models that provide an accurate lower order structure…