A randomised trial of an editorial intervention to reduce spin in the abstract's conclusion of manuscripts showed no significant effect.

Abstract Objective To estimate the effect of an intervention compared to the usual peer-review process on reducing spin in the abstract’s conclusion of biomedical study reports. Study Design and Setting We conducted a two-arm, parallel-group RCT in a sample of primary research manuscripts submitted to BMJ Open. Authors received short instructions alongside the peer reviewers’ comments in the intervention group. We assessed presence of spin (primary outcome), types of spin, and wording change in the revised abstract’s conclusion. Outcome assessors were blinded to the intervention assignment. Results Of the 184 manuscripts randomised, 108 (54 intervention, 54 control) were selected for revision and could be evaluated for the presence of spin. The proportion of manuscripts with spin was 6% lower (95% CI: 24% lower to 13% higher) in the intervention group (57%, 31/54) than in the control group (63%, 34/54). Wording of the revised abstract’s conclusion was changed in 34/54 (63%) manuscripts in the intervention group and 26/54 (48%) in the control group. The four pre-specified types of spin involved: (i) selective reporting (12 in the intervention group versus 8 in the control group); (ii) including information not supported by evidence (9 versus 9); and (iii) interpretation not consistent with study results (14 versus 18); and (iv) unjustified recommendations for practice (5 versus 11). Conclusion These short instructions to authors did not have a statistically significant effect on reducing spin in revised abstract conclusions and, based on the confidence interval, the existence of a large effect can be excluded. Other interventions to reduce spin in reports of original research should be evaluated. Study registration osf.io/xnuyt