Medical education research has changed over the years from merely descriptive studies towards justification or curriculum comparison studies and, nowadays, towards a slow introduction of more clarification studies. In clarification studies quantitative and qualitative methods are used to explain why or how educational interventions work or do not work. This shift is described in this paper. In addition, it is explained how research into workplace learning and assessment has impacted developments in educational practice. Finally, it is argued that the participation of teachers within the medical domain in conducting and disseminating research should be cherished, because they play a crucial role in ensuring that medical education research is applied in educational practice. (Dolmans DHJM, Vleuten CPM van der. Research in medical education: practical impact on medical training and future challenges. Netherlands Journal of Medical Education 2010;29(1):3–9)