Evaluation can naturally inform a cycle of reflection and development. It can help arts and health practitioners establish what is good about what they do, to improve upon it, and to ensure that they are doing nothing that is harmful to participants. In addition, it can help organisations to develop and refine services based upon an informed understanding of the impact they have on participants, and in relation to the needs of commissioners and funders. It can also help to advocate for arts and health projects by showing positive benefits for health and wellbeing