AbstractPurposeVariable assessments of learner performances can occur when different assessors determine different elements to be differently important or salient. How assessors determine the importance of performance elements has historically been thought to occur idiosyncratically and thus be amenable to assessor training interventions. More recently, a main source of variation found among assessors was two underlying factors that were differently emphasised: medical expertise and interpersonal skills. This gave legitimacy to the theory that different interpretations of the same performance may represent multiple truths. A faculty development activity introducing assessors to entrustable professional activities in which they estimated a learner's level of readiness for entrustment provided an opportunity to qualitatively explore assessor variation in the context of an interaction and in a setting in which interpersonal skills are highly valued.MethodsUsing a constructivist grounded theory approach, we explored variation in assessment processes among a group of palliative medicine assessors who completed a simulated direct observation and assessment of the same learner interaction.ResultsDespite identifying similar learner strengths and areas for improvement, the estimated level of readiness for entrustment varied substantially among assessors. Those who estimated the learner as not yet ready for entrustment seemed to prioritise what information was exchanged and viewed missed information as performance gaps. Those who estimated the learner as ready for entrustment seemed to prioritise how information was exchanged and viewed the same missed information as personal style differences or appropriate clinical judgement. When presented with a summary, assessors expressed surprise and concern about the variation.ConclusionA main source of variation among our assessors was the differential salience of performance elements that align with medical expertise and interpersonal skills. These data support the theory that when assessing an interaction, differential salience for these two factors may be an important and perhaps inevitable source of assessor variation.