Introduction The clinical competency committee (CCC) comprises a group of clinical faculty tasked with assessing a medical trainee’s progress from multiple data sources. The use of previously undocumented data, or PUD, during CCC deliberations remains controversial. This study explored the use of previously undocumented data in conjunction with documented data in creating a meaningful assessment in a CCC.

Methods An instrumental case study of a CCC that uses previously undocumented data was conducted. A single CCC meeting was observed, followed by semi-structured individual interviews with all CCC members (n = 7). Meeting and interview transcripts were analyzed iteratively.

Results Documented data were perceived as limited by inaccurate or superficial data, but sometimes served as a starting point for invoking previously undocumented data. Previously undocumented data were introduced as summary impressions, contextualizing factors, personal anecdotes and, rarely, hearsay. The purpose was to raise a potential issue for discussion, enhance and elaborate an impression, or counter an impression. Various mechanisms allowed for the responsible use of previously undocumented data: embedding these data within a structured format; sharing relevant information without commenting beyond one’s scope of experience; clarifying allowable disclosure of personal contextual factors with the trainee pre-meeting; excluding previously undocumented data not widely agreed upon in decision-making; and expecting these data to have been provided as direct feedback to trainees pre-meeting.

Discussion Previously undocumented data appear to play a vital part of the group conversation in a CCC to create meaningful, developmentally focused trainee assessments that cannot be achieved by documented data