Aims A Delphi study to triangulate and determine the relative importance of the key qualities of trainees identified from qualitative interviews that sought to understand how consultant histopathologists determine diagnostic competences in trainees.

Methods Twelve participants were purposively chosen for the Delphi to form an expert panel of relevant stakeholders. Participants were asked to score and rank the items presented to them.

Results A total of 22 out of 27 of the key qualities of trainees (items) reached ‘consensus in’ after round 2 suggesting participants were able to agree that the majority of the items identified in the qualitative interviews were important to diagnostic competence. Five items reached ‘no consensus’. Participants did not suggest any additional items. Participants particularly valued qualities of reflection and professionalism and trainees who understood the process of reaching a diagnosis and how their pathological report could impact on patient care.

Conclusions This study has triangulated findings from our qualitative interviews and show that consultants value a wide variety of qualities when determining diagnostic competence in their trainees. The judgement is complex and is therefore best assessed longitudinally and on a number of cases, so consultants can look for consistency of both approach to diagnosis and of trainee behaviour.