Effect of Monetary Incentives on Peer Review Acceptance and Completion: A Quasi-Randomized Interventional Trial

Objectives: Peer review typically relies on experts volunteering their time to review research. This process presents challenges for journals that may face a shortage of qualified referees, resulting in either delay in handling papers or less thorough review than is optimal. We experimentally tested the impact of providing cash incentives to complete peer review assignments at Critical Care Medicine. Design: Quasi-randomized, blinded, interventional study with an alternating treatment design. Setting: Critical Care Medicine (CCM), a peer-reviewed specialty journal. Subjects: All reviewers receiving requests from CCM to review research articles during a 6-month period from September 2023 to March 2024 (excluding a 2-wk holiday window). Interventions: In alternating 2-week blocks, reviewer invitation letters were sent out, including either an offer of $250 for accepting the peer review request (treatment) or the standard letter with no cash offer (control). Reviewers who fulfilled incentivized invitations received a $250 check from the journal. Measurements and Main Results: Our primary outcome was the rate of invitation-to-completed-review conversion, defined as the number of reviews submitted divided by the number of reviewer invitations sent out. Secondary outcomes included the "on-time"conversion rate, invitation acceptance rate, time to invitation acceptance, time to review submission, and review quality. Seven hundred fifteen reviewer invitations were sent out, 414 of which (57.9%) included an incentive offer. Two hundred eighteen (52.7%) of the incentivized invitations were accepted, compared with 144 (47.8%) in the control group. A greater proportion of reviewer invitations led to submitted peer review reports in the incentive group than in the control group (49.8% [206/414] vs. 42.2% [127/301]; p = 0.04). In a "survival analysis,"invitations sent with an incentive offer were fulfilled faster on average (Cox proportional hazard ratio, 1.30 [1.04-1.62]; p = 0.02), corresponding to quicker review times of approximately 1 day (11 vs. 12 d). Of the 333 reviewer reports submitted, 205 (61.6%) were assessed by editors, with no difference in review quality noted between study arms. Conclusions: Providing cash incentive for completing peer review reports resulted in a modest increase in the share of invited reviewers who complete reviews for a specialty medical journal.