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Form meets function: A commentary on meta‐analytic history

Unlike my colleagues who developed meta-analysis to solve three different research problems—whether selection test validities were generalizable, psychotherapy was effective, or interpersonal expectations influenced behavior—my involvement in meta-analysis came about because I needed a solution to a very different type of problem. In 1980, a mother of a toddler and a newborn, I had just received my PhD in Industrial/Organizational Psychology from the University of Maryland and was looking for a job that would let me combine motherhood and research. Fortunately for me, the Civil Service Reform Act had recently been passed, and agencies of the Federal Government were mandated to create part-time positions for professionals. I was offered a job developing selection tests at the US Office of Personnel Management, and, despite the fact that employee selection was my least favorite subject in graduate school, I accepted the half-time position with alacrity and gratitude. Shortly after my arrival at the US Office of Personnel Management, I met Frank Schmidt, who had by then published his first set of papers (with Jack Hunter and others) on validity generalization. My own education had been at a hotbed of situational specificity (that test validities were largely situationally specific not general), so Frank’s perspective was at first very alien to me. After some animated discussions, I became convinced both of the correctness of the theory of validity generalization and of the usefulness of the method that came to be called meta-analysis. Frank asked me to be a co-author on the seminal “Forty questions about validity generalizations and meta-analysis” (Schmidt, Hunter, Pearlman and Hirsh, 1985), and shortly thereafter, I conducted and then published my first meta-analysis on the generalizability of validities for selection into law enforcement occupations (Hirsh, Northrop and Schmidt, 1986). I have published quite a few meta-analyses since then, but my primary interest over the past 25 years has been how meta-analysis developed and how it is used. It is from this perspective that I comment. The first point I would like to make is that differences in the research questions asked by Glass, Rosenthal, and Schmidt played a great role in what was emphasized by the method of meta-analysis developed by each of its founders and how they see meta-analysis even now. Gene Glass, for example, developed Glassian meta-analysis to demonstrate the effectiveness of psychotherapy as a treatment for psychological problems. I suggest that, in large part, it is because he used meta-analysis to test the effectiveness of an intervention that he views metaanalysis as being about the evaluation of technologies and not about the testing of theories (Glass, 2015). Of course, if we look at the application of meta-analysis, it is true that the majority of applications have been to assess the effectiveness of interventions (consider, for example, the thousands of meta-analyses published by the Cochrane and Campbell Collaborations). This does, not, however, mean that meta-analysis is fundamentally unsuited to theory testing. As Frank Schmidt notes elsewhere in this issue (Schmidt, 2015), his and Jack Hunter’s original development of validity generalization was to provide evidence to refute the theory of situational specificity. There are many other uses of meta-analysis to test theories; I will mention two that I think deserve particular attention because of the broad impact they have had in their respective fields. One is Alice Eagly and colleagues’ programmatic meta-analytic work examining social role theory as an explanation for gender similarities, differences, and stereotypes particularly in the area of leadership (cf. Eagly et al., 2003; Eagly and Johnson, 1990; and Koenig et al., 2011). The other is Jessica Gurevitch and colleagues’ meta-analysis on the role of competition in natural populations, which put an end to a decades-long theoretical controversy by providing overwhelming evidence for the importance and ubiquity of competition in nature across many different groups of organisms in many different kinds of ecological communities (Gurevitch et al., 1992).