Peer review reduces spin in PCORI research reports.

Background: The Patient-Centered Outcomes Research Institute (PCORI) is obligated to peer review and to post publicly "Final Research Reports" of all funded projects. PCORI peer review emphasizes adherence to PCORI's Methodology Standards and principles of ethical scientific communication. During the peer review process, reviewers and editors seek to ensure that results are presented objectively and interpreted appropriately, e.g., free of spin.

Methods: Two independent raters assessed PCORI peer review feedback sent to authors. We calculated the proportion of reports in which spin was identified during peer review, and the types of spin identified. We included reports submitted by April 2018 with at least one associated journal article. The same raters then assessed whether authors addressed reviewers' comments about spin. The raters also assessed whether spin identified during PCORI peer review was present in related journal articles.

Results: We included 64 PCORI-funded projects. Peer reviewers or editors identified spin in 55/64 (86%) submitted research reports. Types of spin included reporting bias (46/55; 84%), inappropriate interpretation (40/55; 73%), inappropriate extrapolation of results (15/55; 27%), and inappropriate attribution of causality (5/55; 9%). Authors addressed comments about spin related to 47/55 (85%) of the reports. Of 110 associated journal articles, PCORI comments about spin were potentially applicable to 44/110 (40%) articles, of which 27/44 (61%) contained the same spin that was identified in the PCORI research report. The proportion of articles with spin was similar for articles accepted before and after PCORI peer review (63% vs 58%).

Discussion: Just as spin is common in journal articles and press releases, we found that most reports submitted to PCORI included spin. While most spin was mitigated during the funder's peer review process, we found no evidence that review of PCORI reports influenced spin in journal articles. Funders could explore interventions aimed at reducing spin in published articles of studies they support.