The assessment of a large portfolio of mainly textual evidence demands an assessor to accommodate a great deal of information. This comprehension process is influenced by the linear nature of the reading process which leads to the gradual construction of a mental representation of the text in the head of the reader (Johnson and Laird, 1983).

Understanding how assessors work with portfolios also requires us to consider how assessors integrate and combine different aspects of an holistic performance into a final judgement. Sanderson (2001) suggests that the social context of the assessor is important to consider since it recognises their participation in a community of practice (Wenger, 1998) and constitutes an 'outer frame' for their activity.

This study sought to explore issues of consistent assessor judgement by gathering data about individual assessors' cognitive activity as well as the socio-contextual features in which their practices were undertaken. It focused on an OCR Nationals unit in Health and Social Care (Level 2). Six assessors were asked to 'think aloud' whilst they judged the unit. This commentary was then transcribed into a verbal protocol and analysed with qualitative text analysis software. A modified Kelly's Repertory Grid (KRG) interview technique was also used to gather data about different assessors' perceptions of constructs within the same assessment criteria.