Background: During clinical placements, supervisors repeatedly assess health and medical students for competence. Quality assessment is dependent upon the supervisors having a rich understanding of entry-level standards and an assessment approach that is sufficiently dynamic to accommodate the changing healthcare system. This study aimed to assess whether consensus could be gained by supervisors when assessing the performance of student dietitians during clinical placements and to establish a shared interpretation of entry-level clinical competence. Methods: A modified 3-round Delphi study with a focus group discussion was conducted with eight supervisors. Participants were required to assess the performance of student dietitians from audiovisual recordings of authentic student‒client consultations in aged-care and outpatient settings. Results: Consensus was achieved for 2/11 assessments after one Delphi round, 6/11 assessments after two rounds and 10/11 assessments after the third and final round. During the focus group discussion, the expert panel expressed a shared understanding of entry-level performance, however this was not transferred into a shared assessment of entry-level performance in the Delphi task. Conclusions: Dialogue amongst supervisors leads to a more reliable interpretation of the competency standards. A shared responsibility for assessment, with continuous and open negotiation of meaning, is required to ensure quality assessments of entry-level practice.