It combines theory and practical recommendations to help teachers understand the principles of testing and how they can be applied, supporting them to write better tests. The third edition has been extensively revised and updated to reflect developments in the field, while retaining the straightforward approach that made the earlier editions essential reading for trainee and experienced teachers alike. It features new content on technology, including computer adaptive testing and the use of automated scoring for all skills. It also includes an extended discussion of language testers' responsibilities and new chapters on non-testing methods of assessment.