Participatory evaluation gives primacy to the experience of people affected by the policy. How realistic is it for researchers to persuade government of its benefits, given the gap between participatory policy theory and government evaluation practice? We apply this question to the Resident Support Program evaluation. The program coordinates support for people living in boarding houses and hostels in Queensland, Australia. We found that a participatory, longitudinal, formative evaluation process facilitated service user contribution to research outcomes, service experiences and policy implementation. In addition, the values position of participatory research can contribute to managing interest conflict in policy implementation.