This paper reports on the development and piloting of a systematic review and meta analysis of research on the effectiveness of problem based learning (PBL). The systematic review protocol was pilot tested with a sample of studies cited as providing "evidence" about the effectiveness of PBL. From the 5 studies mentioned in the sample of reviews, 91 citations were identified, and 15 of these were adjudged to meet the review inclusion criteria. Of the 15, only 12 reported extractable data. All of these studies used PBL in higher education programs for health professional education. The review has established that the limited high quality evidence available from existing reviews does not provide robust evidence about the effectiveness of different kinds of PBL in different contexts with different student groups. It is apparent that there is scope for a systematic review of PBL that is specific in terms of the intervention being evaluated, comprehensive in terms of strategy used, and methodologically rigorous. One appendix contains the coding sheet used, and the other is a bibliography of reviewed papers. The second part of the paper is the review protocol. (Contains 1 figure, 10 tables, and 91 references.) (SLD)