The impact of public involvement in health research: what are we measuring? Why are we measuring it? Should we stop measuring it?

As public involvement in the design, conduct and dissemination of health research has become an expected norm and firmly enshrined in policy, interest in measuring its impact has also grown. Despite a drive to assess the impact of public involvement, and a growing body of studies attempting to do just this, a number of questions have been largely ignored. This commentary addresses these omissions: What is the impact of all this focus on measuring impact? How is the language of impact shaping the debate about, and the practice of, public involvement in health research? And how have shifting conceptualisations of public involvement in health research shaped, and been shaped by, the way we think about and measure impact? We argue that the focus on impact risks distorting how public involvement in health research is conceptualised and practised, blinding us to possible negative impacts. We call for a critical research agenda for public involvement that [a] considers public involvement not as an instrumental intervention but a social practice of dialogue and learning between researchers and the public; [b] explores how power relations play out in the context of public involvement in health research, what empowerment means and whose interests are served by it, and [c] asks questions about possible harms as well as benefits of public involvement, and whether the language of impact is helpful or not.