The National Institute for Health Research (NIHR) is a major funder of health research in the United Kingdom. Selecting the most promising studies to fund is crucial, and external expert peer review is used to inform the funding boards. Our aim was to evaluate the influence of different kinds and numbers of peer review and reviewer scores on Board funding decisions, and how we might modify the process to reduce the workload for stakeholders.

Our mixed method study included i) retrospective cross sectional analysis of funding board and external reviewer scores for second stage applications for research funding, using Receiver Operator Characteristic (ROC) curves to quantify the influence of reviewer scores on funding decisions and ii) qualitative interviews with thirty stakeholders (funding board members, applicants, external peer reviewers and NIHR staff).

Analysis of ROC area for reviewers indicated that areas changed very little with increasing numbers of reviewers from four to seven or more. External reviewers with clinical, methodological or patient expertise all appeared to influence Board funding decisions to a similar extent. The stakeholders interviewed valued peer review but felt it was important to develop a more proportionate process, to better balance its benefit with the workload of obtaining, preparing, reading and responding to reviews. Reviews are of most value when they fill gaps in expertise on the Board. Less than four reviews was felt to be insufficient but more than six, excessive. Workload could be reduced by making reviews more focused on the strengths and weaknesses of applications and identifying flaws which are potentially “fixable”.

Stakeholders supported the need for peer review in evaluating funding applications. Our results suggest that four to six peer reviews per application is optimum, depending on the expertise needed to complement that of advisory boards.