Defining the construct of interaction for paired assessment purposes has been difficult, despite the evolution of our view of language to include the social perspective of co-construction, and the fact that such discourse is increasingly taught and assessed. In this volume three sequenced studies define interaction in paired oral assessment through the verbal protocols of learners of Spanish and their assessors. Assessors then scale performances from videoed test performance data resulting in the development of an evidence based rating process which includes non-verbal interpersonal communication, interactive listening and interactional management.