DOES PROBLEM-BASED LEARNING WORK - A METAANALYSIS OF EVALUATIVE RESEARCH

The purpose of this review is to synthesize all available evaluative r esearch from 1970 through 1992 that compares problem-based learning (P BL) with more traditional methods of medical education. Five separate meta-analyses were performed on 35 studies representing 19 institution s. For 22 of the studies (representing 14 institutions), both effect-s ize and supplementary vote-count analyses could be performed; otherwis e, only supplementary analyses were performed. PBL was found to be sig nificantly superior with respect to students' program evaluations (i.e ., students' attitudes and opinions about their programs)-dwBAR (stand ardized differences between means, weighted by sample size) = +.55, CI .95 = +.40 to +.70-and measures of students' clinical performance (dwB AR = +.28, CI.95 = +.16 to +.40). PBL and traditional methods did not differ on miscellaneous tests of factual knowledge (dwBAR = -.09, CI.9 5 = +.06 to -.24) and tests of clinical knowledge (dwBAR = +.08, CI.95 = -.05 to +.21). Traditional students performed significantly better than their PBL counterparts on the National Board of Medical Examiners Part I examination-NBME I (dwBAR = -.18, CI.95 = -.10 to -.26). Howev er, the NBME I data displayed significant overall heterogeneity (Q(t) = 192.23, p <.001) and significant differences among programs (Q(b) = 59.09, p < .001), which casts doubt on the generality of the findings across programs. The comparative value of PBL is also supported by dat a on outcomes that have been studied less frequently, i.e., faculty at titudes, student mood, class attendance, academic process variables, a nd measures of humanism. In conclusion, the results generally support the superiority of the PBL approach over more traditional methods.