AbstractBackgroundMedical schools increasingly incorporate teamwork in their curricula but medical students often have a negative perception of team projects, in particular when there is unequal participation. The purpose of this study is to evaluate whether a novel peer evaluation system improves teamwork contributions and reduces the risk of students “free loading”.MethodsA cluster randomised controlled trial (RCT) with qualitative follow up enrolled 37 teams (n = 223 students). Participating teams were randomised to intervention group (19 teams) or control group (18 teams). The validated Comprehensive Assessment Team Member Effectiveness (CATME) tool was used as the outcome measure, and was completed at baseline (week 2) and at the end of the project (week 10). The team contribution subscale was the primary outcome, with other subscales as secondary outcomes. Six focus group discussions were held with students to capture the team’s experiences and perceptions of peer assessment and its effects on team work.ResultsThe results of the RCT showed that there was no difference in team contribution, and other forms of team effectiveness, between intervention and control teams. The focus group discussions highlighted students’ negative attitudes, and lack of implementation of this transparent, points-based peer assessment system, out of fear of future consequences for relationships with peers. The need to assess peers in a transparent way to stimulate open discussion was perceived as threatening by participants. Teams suggested that other peer assessment systems could work such as rewarding additional or floating marks to high performing team members.ConclusionsOther models of peer assessment need to be developed and tested that are non-threatening and that facilitate early acceptance of this mode of assessment.