What do we know about grant peer review in the health sciences?

Background: Peer review decisions award an estimated >95% of academic medical research funding, so it is crucial to understand how well they work and if they could be improved. Methods: This paper summarises evidence from 105 papers identified through a literature search on the effectiveness and burden of peer review for grant funding. Results: There is a remarkable paucity of evidence about the efficiency of peer review for funding allocation, given its centrality to the modern system of science. From the available evidence, we can identify some conclusions around the effectiveness and burden of peer review. The strongest evidence around effectiveness indicates a bias against innovative research. There is also fairly clear evidence that peer review is, at best, a weak predictor of future research performance, and that ratings vary considerably between reviewers. There is some evidence of age bias and cronyism. Good evidence shows that the burden of peer review is high and that around 75% of it falls on applicants. By contrast, many of the efforts to reduce burden are focused on funders and reviewers/panel members. Conclusions: We suggest funders should acknowledge, assess and analyse the uncertainty around peer review, even using reviewers' uncertainty as an input to funding decisions. Funders could consider a lottery element in some parts of their funding allocation process, to reduce both burden and bias, and allow better evaluation of decision processes. Alternatively, the distribution of scores from different reviewers could be better utilised as a possible way to identify novel, innovative research. Above all, there is a need for open, transparent experimentation and evaluation of different ways to fund research. This also requires more openness across the wider scientific community to support such investigations, acknowledging the lack of evidence about the primacy of the current system and the impossibility of achieving perfection.