The validation of language tests is widely discussed and expected, but only in recent years have researchers adopted a variety of innovative techniques for developing, assessing and validating specific tests of second or foreign language proficiency and their impact on education and society. Indeed, as the present volume clearly demonstrates, many different techniques for empirical analysis and types of evidence may be used to assess and interpret the validity of diverse aspects of language tests as well as the consequences they may have for language students, educators and society. The 12 chapters in this book are by leading researchers in different parts of the world, each originally presented at the 14th Annual Language Testing Research Colloquium. An introductory chapter reviews theories of test validation and distinguishes how each of the 12 chapters serves as a unique case study in establishing the validity of a specific language test, its uses, or its societal impact. The volume will be of interest to all persons working with language tests, educational and government administrators and researchers, and graduate students of evaluation in second or foreign languages.