Improving peer review of systematic reviews and related review types by involving librarians and information specialists as methodological peer reviewers: a randomised controlled trial.

Objective: To evaluate the impact of adding librarians and information specialists (LIS) as methodological peer reviewers to the formal journal peer review process on the quality of search reporting and risk of bias in systematic review searches in the medical literature.

Design: Pragmatic two-group parallel randomised controlled trial.

Setting: Three biomedical journals.

Participants: Systematic reviews and related evidence synthesis manuscripts submitted to , and and sent out for peer review from 3 January 2023 to 1 September 2023. Randomisation (allocation ratio, 1:1) was stratified by journal and used permuted blocks (block size=4). Of 2670 manuscripts sent to peer review during study enrollment, 400 met inclusion criteria and were randomised (62 , 334 , 4 ). 76 manuscripts were revised and resubmitted in the intervention group and 90 in the control group by 2 January 2024.

Interventions: All manuscripts followed usual journal practice for peer review, but those in the intervention group had an additional (LIS) peer reviewer invited.

Main Outcome Measures: The primary outcomes are the differences in first revision manuscripts between intervention and control groups in the quality of reporting and risk of bias. Quality of reporting was measured using four prespecified PRISMA-S items. Risk of bias was measured using ROBIS Domain 2. Assessments were done in duplicate and assessors were blinded to group allocation. Secondary outcomes included differences between groups for each individual PRISMA-S and ROBIS Domain 2 item. The difference in the proportion of manuscripts rejected as the first decision post-peer review between the intervention and control groups was an additional outcome.

Results: Differences in the proportion of adequately reported searches (4.4% difference, 95% CI: -2.0% to 10.7%) and risk of bias in searches (0.5% difference, 95% CI: -13.7% to 14.6%) showed no statistically significant differences between groups. By 4 months post-study, 98 intervention and 70 control group manuscripts had been rejected after peer review (13.8% difference, 95% CI: 3.9% to 23.8%).

Conclusions: Inviting LIS peer reviewers did not impact adequate reporting or risk of bias of searches in first revision manuscripts of biomedical systematic reviews and related review types, though LIS peer reviewers may have contributed to a higher rate of rejection after peer review.

Trial Registration Number: Open Science Framework: https://doi.org/10.17605/OSF.IO/W4CK2.