This chapter discusses the collection of evaluative evidence and considers the implications of this evidence for Task-Based Language Teaching (TBLT) as a viable educational endeavour. It goes on to focus predominantly on the classroom-based use of communicative tasks for assessment purposes in local contexts. The chapter then considers the use of different kinds of assessment instruments to gather a range of evidence on students’ learning outcomes. Gipps spoke of a “paradigm shift” in educational assessment that began to challenge the accepted orthodoxy that tests and examinations should be central and that embraced a broader model. In the case of a construct-based assessment, the construct definition becomes the springboard or foundation from which to devise an appropriate task for assessment purposes. The chapter concludes with a brief discussion of how the practice of TBLT in classrooms may be influenced by so-called high-stakes assessment systems.