OBJECTIVE: To evaluate how the size of an outcome adjudication committee, and the potential for dominance among its members, potentially impacts a trial's results. STUDY DESIGN AND SETTING: We conducted a retrospective analysis of data from the six-member adjudication committee in the Study to Prospectively Evaluate Reamed Intramedullary Nails in Patients with Tibial Fractures (SPRINT) Trial. We modeled the adjudication process, predicted the results and costs if smaller committees had been used, and tested for the presence of a dominant adjudicator. RESULTS: Use of smaller committee sizes (one to five members) would have had little impact on the final study results, although one analysis suggested that the benefit in reduction of reoperations with reamed nails in closed tibial fractures would have lost significance if committee sizes of three or less were used. We identified a significant difference between adjudicators in the number of times their original minority decisions became the final consensus decision (chi(2)=9.67, P=0.046), suggesting that dominant adjudicators were present. However, their impact on the final study results was trivial. CONCLUSION: Reducing the number of adjudicators from six to four would have led to little change in the final SPRINT study results irrespective of the significance of the original trial results, demonstrating the potential for savings in trial resources.