Problem-based learning has been used in medical school in a number of different countries around the world for over 50 years, with both undergraduate and graduate students. Instead of the traditional lectures, laboratory practical classes and tutorial system of education, students in small groups are presented with a problem that they must try to solve. They are assisted by a 'facilitator' who helps them formulate the problem and generally advises them but does not supply information. The students have to decide what information they need to solve the problem, find it and communicate it to the others in the group. At this stage a solution may be apparent, but several more group discussions to reformulate the problem followed by re-iterations of the information seeking process may be needed before a solution can be found. The theory is that because information is sought and presented in a relevant context, it is valued and is more likely to be remembered. At the end of the session student reflect on how they performed. Problem-based learning has been criticised from a number of points of view, especially that it does not present a coherent curriculum, the curriculum is not necessarily 'covered', and that in many medical schools the implementation has been less than optimal.