Introduction: Competency based medical education (CBME) requires that educators structure assessment of clinical competence using outcome frameworks. While these frameworks may serve some outcomes well (e.g., represent eventual practice), translating these into workplace‐based assessment plans may undermine validity and, therefore, trustworthiness of assessment decisions due to a number of competing factors that may not always be visible or their impact knowable. Explored here is the translation process from outcome framework to formative and summative assessment plans in postgraduate medical education (PGME) in three Canadian universities. Methods: We conducted a qualitative study involving in‐depth semi‐structured interviews with leaders of PGME programs involved in assessment and/or CBME implementation, with a focus on their assessment‐based translational activities and evaluation strategies. Interviews were informed by Callon’s theory of translation. Our analytical strategy involved directed content analysis, allowing us to be guided by Kane’s validity framework, whilst still participating in open coding and analytical memo‐taking. We then engaged in axial coding to systematically explore themes across the dataset, various situations and our conceptual framework. Results: Twenty‐four interviews were conducted involving 15 specialties across three universities. Our results suggest (a) using outcomes for assessment frameworks serves as necessary for good assessment but also as an incomplete construct; (b) there are a number of social and practical negotiations with competing factors that displace validity as a core influencer in assessment planning, including implementation, accreditation and technology; (c) validity exists as threatened, uncertain and assumed due to a number of unchecked assumptions and reliance on surrogates. Conclusions: Translational processes in CBME involve negotiating with numerous influencing actors and institutions that, from an assessment perspective, provide challenges for assessment scientists, institutions and educators to contend with. These processes are challenging validity as a core element of assessment designs. Educators must reconcile these influences when preparing for or structuring validity arguments.