Learner handover (LH), the process of sharing of information about learners between faculty supervisors, allows for longitudinal assessment fundamental in the competency-based education model. However, the potential to bias future assessments has been raised as a concern. The purpose of this study is to determine whether prior performance information such as LH influences the assessment of learners in the clinical context. Between December 2017 and June 2018, forty-two faculty members and final-year residents from the Department of Medicine at the University of Ottawa were assigned to one of three study groups through quasi-randomisation, taking into account gender, speciality and rater experience. In a counter-balanced design, each group received either positive, negative or no LH prior to watching six simulated learner--patient encounter videos. Participants rated each video using the mini-CEX and completed a questionnaire on the raters' general impressions of LH. A significant difference in the mean mini-CEX competency scale scores between the negative (M = 5.29) and positive (M = 5.97) LH groups (P < 0.001, d = 0.81) was noted. Similar findings were found for the single overall clinical competence ratings. In the post-study questionnaire, 22/28 (78%) of participants had correctly deduced the purpose of the study and 14/28 (50%) felt LH did not influence their assessment. LH influenced mini-CEX scores despite raters' awareness of the potential for bias. These results suggest that LH could influence a rater's performance assessment and careful consideration of the potential implications of LH is required.