Meta-Analysis: A Systematic Method for Synthesizing Counseling Research

Article excerpt

In response to the theme of this special section on getting published in counseling journals, the purpose of this article is to provide an overview of steps in conducting a meta-analysis. Meta-analysis has been increasingly recognized as a methodologically sound approach to synthesizing research (Cooper, 2010; Cooper, Robinson, & Dorr, 2006). The purpose of meta-analysis is to quantitatively aggregate the results of numerous empirical studies on a topic of interest (Erford, Savin-Murphy, & Butler, 2010). It can be a particularly attractive endeavor for researchers and practitioners who have been working within a specific area for some time or for doctoral students who have completed very comprehensive literature reviews. The term meta-analysis was first coined by Gene V. Glass in 1976. Meta is a Greek word that means "behind" or "in back of," but Glass (2000) emphasized that meta-analysis "is not the grand theory of research; it is simply a way of speaking of the statistical analysis of statistical analyses." He defined meta-analysis as "the statistical analysis of a large collection of analysis results from individual studies for purpose of integrating the findings" (Glass, 1976, p. 3).

Counseling researchers may want to consider meta-analytic reviews because their efforts could result in major contributions to the field. As a type of literature review, a meta-analysis aggregates research studies that usually are published in diverse journals (e.g., education, social work, psychology). Therefore, counseling practitioners often appreciate meta-analytic studies in which researchers systematically analyze research findings from diverse journals because practitioners often do not have time to read a wide variety of journals. Furthermore, meta-analytic researchers are increasingly including unpublished studies such as dissertations and theses in their quantitative reviews, which can further expand the comprehensive nature of a meta-analytic review and increase the degree to which the results are useful. Meta-analyses, moreover, can supplement traditional qualitative literature reviews because the process produces effect sizes, which are quantitative indices of the practical significance of the effect. For example, meta-analytic procedures can determine the magnitude of results of a counseling treatment over no treatment or the level of association between attending counseling sessions and well-being. With the current focus on the empirical support for treatment approaches (e.g., evidence-based practices), meta-analysis can provide useful information regarding the degree of empirical support for a type of treatment. This, however, should not be taken to mean that meta-analytic studies are the only source of evidence-based practices.

Durlak (1995) contended that conducting a meta-analysis is analogous to conducting a single scientific experiment in the social or behavioral sciences. As compared with collecting data from participants, in a meta-analysis, the data are collected from individual studies. Hence, rather than doing statistical analyses on the data gathered from multiple participants, the statistical analyses in meta-analyses are conducted on data gathered from multiple studies. Later in this article, we will discuss steps in conducting a meta-analysis, which will include formulating a research question and then finding studies that are specifically related to that question. Similar to other types of quantitative studies, with meta-analyses there are independent and dependent variables. In counseling research, many of the meta-analyses have focused on examining the effectiveness of different interventions, programs, or therapeutic modalities (Erford et al., 2010). In these studies, the dependent variable is some measure of effectiveness (e.g., well-being, level of depression, symptomatology) and the independent variables are study variables (e.g., client age, counselor training, types of treatment). …