This book analyses oral proficiency interviews, a mainstay of second language speaking proficiency assessment for several decades. Adopting a mixed-method perspective involving micro-analytic approaches, discourse analysis and quantitative methods such as multi-level modeling and event history analysis, the author focuses on interaction and discourse processes common in language assessment interviews. This innovative book will appeal to students and scholars of language assessment, conversation and discourse analysts, as well as practitioners and providers of oral proficiency assessment.