This study investigated the cognitive strategies that underpin assessors' holistic judgments of a school-based vocationally-related portfolio performance. Using a portfolio already identified as containing borderline qualities, quantitative data were gathered about features that six assessors attended to as they holistically evaluated the portfolio. This information was gathered through verbal protocols and supplemented with information from a modified Kelly's Repertory Grid interview technique (Kelly, 1955). This elicited assessors' perceptions about the characteristics of the assessment criteria, allowing the influence of each factor to be ranked. Another objective was to collect qualitative data about the socio-contextual features in which the assessors' practices were situated. The study uses Activity Theory to explore the relationship between the factors that potentially influence assessors' judgments, suggesting a theoretical position that assessor judgments are influenced or framed within the context of their experience and differing perspectives. (Contains 3 tables and 1 figure.)