Biomedical research funding bodies across Europe and North America increasingly encourage—and, in some cases, require—investigators to involve members of the public in funded research. Yet there remains a striking lack of clarity about what ‘good’ or ‘successful’ public involvement looks like. In an effort to provide guidance to investigators and research organisations, representatives of several key research funding bodies in the UK recently came together to develop the National Standards for Public Involvement in Research. The Standards have critical implications for (...) the future of biomedical research in the UK and in other countries as researchers and funders abroad look to the Standards as a model for their own policy development. We assess the Standards and find that despite offering useful suggestions for dealing with practical challenges associated with public involvement, the Standards fail to address fundamental questions about when, why and with whom public involvement should be undertaken in the first place. We show that presented without this justificatory context, many of the recommendations in the Standards are, at best, fragments that require substantial elaboration by those looking to apply the Standards in their own work and, at worst, subject to potentially harmful misapplication by well-meaning investigators. As funding bodies increasingly push for public involvement in research, the key lesson of our analysis is that future recommendations about how public involvement should be conducted cannot be coherently formulated without a clear sense of the underlying goals and rationales for public involvement. (shrink)