The concept of competence is crucial for evaluating educational systems as well as for basic research in education. This book covers current theoretical, psychometric, and practical issues related to the assessment of competencies in educational and vocational settings. Leading researchers from around the world contribute their expertise from different research fields. The first part of the book provides theoretical perspectives on the concept of competencies in educational and vocational contexts, as well as on developmental models. The second part deals with item writing and psychometric models for assessing and explaining competencies. In addition, practical issues such as test construction, computer-based assessment, and the implementation of assessment tools in school contexts are addressed. The book is of interest not only for researchers interested in theoretical and psychometric background of assessment, but also for readers interested in practical aspects of computer-based assessment and evaluation in educational or vocational contexts, such as policy makers, teachers, and school administrators.