RCTs have important limitations in evaluating educational interventions

Learning in practice p 153

Problem based learning, an educational intervention characterised by small group and self directed learning, is one of medical education's more recent success stories, at least in terms of its ubiquity. From its beginnings in McMaster University in the 1960s it has been adopted in undergraduate medical courses worldwide. It is also being used in postgraduate and continuing medical education.

Problem based learning has been the subject of at least four much quoted reviews, three published in the early 1990s and one more recently.1^–4 Such attention is not surprising. What might be surprising is that the effects of such a popular educational approach are seemingly small, except in the area of student satisfaction. According to the reviews the extent of knowledge gained by such measures as performance in licensing examinations is at best unclear. Participants in problem based learning, however, can expect small gains in clinical reasoning.

The paper by Smits and colleagues in this …