This article explores the nature of the construct underlying classroom-based English for academic purpose (EAP) oral presentation assessments, which are used, in part, to determine admission to programmes of study at UK universities. Through analysis of qualitative data (from questionnaires, interviews, rating discussions, and fieldnotes), the article highlights how, in EAP settings, there is a tendency for the rating criteria and EAP teacher assessors to sometimes focus too narrowly on particular spoken linguistic aspects of oral presentations. This is in spite of student assessees drawing on, and teacher assessors valuing, the multimodal communicative affordances available in oral presentation performances. To better avoid such construct underrepresentation, oral presentation tasks should be acknowledged and represented in rating scales, teacher assessor decision-making, and training in EAP contexts.