The consumer/ex-patient movement has moved the field of psychosocial rehabilitation to new ground with respect to the consumer's role in service planning and evaluation. In a similar fashion, a methodology called Participatory Action Research (PAR) offers a paradigm for involving consumers in rehabilitation research and program evaluation efforts. The development of this paradigm is discussed as are the benefits and potential drawbacks to using this approach, the way in which PAR differs from traditional research, and the implications for policymakers, researchers and evaluators.