Differential Effectiveness of Prevalent Social Work Practice Models: A Meta-Analysis

Within the past few decades, an increasing number of group outcome studies on the effectiveness of social work have been published. As this has occurred, various social workers have prepared narrative review articles that critically summarize their findings. Among the reviews of this type are Segal (1972); Fischer (1973); Reid and Hanrahan (1982); Sheldon (1986); MacDonald, Sheldon, and Gillespie (1992); Rubin (1985); and Thomlison (1984). Although such reviews have certainly performed a valuable professional service, their qualitative interpretive methods are often not replicable, and so they may leave the potentially potent alternative or confound explanation of reviewer bias essentially uncontrolled. The methodological refinement of meta-analysis, which calls for the specific explication of sampling (study selection) and analytic (effect size [ES] calculations) procedures, offers some control against such reviewer bias (Cooper, 1989; Wolf, 1986). Although meta-analysis has long been used in the fields of medicine and psychology (for example, Smith & Glass, 1977), to date only two meta-analytic studies of social work practice have been published. The first of these appeared in 1988 and was prepared by Videka-Sherman. Her conclusions were comforting and generous (Videka-Sherman, 1988): "social work intervention has a positive effect on outcome (p. 328) [and] . An empirical basis on which to claim effectiveness of social work practice in mental health exists" (p. 329). Hogarty (1989) subsequently published a substantive critique of Videka-Sherman's study, claiming serious problems with the meta-analysis itself and inappropriate characterizations of social work practice, concluding, "this exercise not only resulted in questionable conclusions but also served to illustrate abiding problems in the design, methods, and analysis of social work research efforts" (p. 363). Given Hogarty's considerable stature as a clinical researcher in the field of chronic mental illness (Hogarty, 1991), the focal point of Videka-Sherman's study, his criticisms seemed to mute subsequent discussion of this initial meta-analytic study. More recently, Gorey (1996) published a meta-analysis of contemporary social work effectiveness studies, covering those published from 1990 to 1994. Eighty-eight studies were selected from 13 journals, eight of which were affiliated with professional social work associations. Effect sizes were estimated using a metric called the r-index, interpretable as the Pearson's linear correlation coefficient, which provides an estimate of the strength of the social work intervention-outcome relationship. The focus of Gorey's original meta-analytic report was to compare the ESs generated by internal versus external evaluations of effectiveness. A study that used social workers' assessments of the outcomes of their own practice was classified as an internal evaluation, whereas one using assessments by others unconnected with service delivery was labeled as an external evaluation. The mean r-index for all 88 studies was . 356 (SD = .261, p [less than] .001), permitting the conclusion that about 78 percent (based on conversion to another ES metric, Cohen's [1988] [U.sub.3] of 77.7 percent) of the clients who received social work intervention did better than the average client who did not. Moreover, others have replicated this overall finding among unpublished social work research sources (theses, dissertations, or conference proceedings); so mere publication bias is not likely as the explanation (de Smidt & Gorey, 1997; Grenier & Gorey, in press). When the studies using internal evaluations of outcome were compared with external evaluations, it was found that although both produced positive ESs, the internal evaluations were significantly more favorable than the external [mean r of.518 compared to . 186, t(86) = 7.93, p [less than] . 001]. In other words, "social workers evaluating their own direct practice or their agencies' programs tended to report more favorable findings than evaluators who were not directly involved in the work" (Gorey, 1996, p. …