To bridge the gap between scientific evidence and patient care we need an in-depth understanding of the barriers and incentives to achieving change in practice. Various theories and models for change point to a multitude of factors that may affect the successful implementation of evidence. However, the evidence for their value in the field is still limited. When planning complex changes in practice, potential barriers at various levels need to be addressed. Planning needs to take into account the nature of the innovation; characteristics of the professionals and patients involved; and the social, organisational, economic and political context.