Quantitative methods of evaluating the outcomes of medical education may not always deliver the information which course organizers and teachers most need in order to improve their courses. Qualitative methods of research could provide such information. However, the use of qualitative methods has been limited by the difficulties associated with the analysis of subjective data and by the validity of its results. Qualitative data from an evaluation of the 2-year part-time MSc Course in General Practice at Guy's and St Thomas's Hospitals are presented and a rigorous method of analysis demonstrated. It is argued that for qualitative research validity is progressively achieved through the process of analysis, unlike experimental research where validity is ascribed in the research design. The relationship of research methods and approaches to evaluation is discussed and the potential contribution of qualitative research methods is outlined.