ABSTRACT
Since its introduction into the organizational research literature 25 years ago (Schmidt & Hunter, 1977), meta-analysis has been the focus of numerous conceptual and methodological controversies and developments. Before we delve into some of those issues, let us first remember that meta-analysis can be seen as essentially two things: (a) statistically, it provides an estimate of the mean and variance of the effect size estimates across studies (e.g., correlations, d-values, odds ratios); and (b) more broadly, it provides a statistically and rationally driven process of identifying, gathering, coding, combining, and interpreting results across studies. Clearly these two characterizations of meta-analysis are interrelated: Conceptual and practical considerations inform the decision points regarding what research data to summarize and how to summarize them (Matt, 1989; Wanous, Sullivan, & Malinak, 1989), and in turn, the statistical results and substantive interpretation from meta-analysis inform further research and practice.
