Clinical supervision research from 1981 to 1993: A methodological critique

The empirical studies in clinical supervision published from 1981 through 1993 were investigated to assess scientific rigor and to test whether the quality of methodology had improved since the review by R. K. Russell, A. M. Crimmings, and R. W. Lent (1984). The 144 studies were evaluated according to 49 threats to validity (T. D. Cook. & D. T. Campbell, 1979; R. K. Russell et al., 1984; B. E. Wampold, B. Davis, & R. H. Good III, 1990) and 8 statistical variables (e.g., effect size, statistical power, and Type I and Type II error rates). The data revealed a shift to realistic field studies, unchecked Type I and Type II error rates, medium effect sizes, and inattention to hypothesis validity. Recommendations for designing and conducting a feasible and well-designed supervision study are offered.