Research Methods in Family Therapy

KAREN S. WAMPLER
ALAN REIFMAN
JULIANNE M. SEROVICH

“Meta-analysis” is an empirical methodology for summarizing findings from different quantitative research studies on a given topic. It stands in marked contrast to the typical narrative review of literature, in which conclusions are based on a general summary of statistically significant and nonsignificant findings. In meta-analysis, a common metric known as “effect size,” such as the product–moment correlation or the standardized difference between two groups—for example, (M_e – M_c)/SD_pooled—is used to represent a study finding. The study finding, as represented by this number, becomes a data point and can be used in any number of creative ways to statistically analyze what is known from many different research studies on a topic.

Meta-analysis is a precise and powerful way of providing information important to the field of marriage and family therapy (MFT) for any question on which multiple relevant quantitative studies have been conducted. Its purposes are to (1) summarize what is known; (2) assess the relations among study findings, variables, and methodology; (3) suggest recommendations for future research, including identifying areas in which little further research is needed; (4) develop and test models and theoretical propositions across samples; and/or (5) generate policy and practice implications (Carson, Schriesheim, & Kinicki, 1990; Durlak & Lipsey, 1991; Wampler, 1982a).

One important function of meta-analysis has been to summarize the effectiveness of psychotherapy. Rather than reading numerous separate studies, clinicians and policymakers can read a summary of the research that is couched in terms of easily understood numbers. Two examples of interest to MFT practitioners are the article by Lipsey and Wilson (1993), summarizing over 302 different meta-analyses of treatments in psychotherapy, prevention, and education, and the comprehensive metaanalysis by Shadish and colleagues (1993) of MFT outcome studies. More recently,

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