Presents current theoretical, psychometric, and practical issues related to the assessment of competencies within various educational settings. Psychometric models for assessing and predicting competencies and measuring change are outlined and discussed while practical issues such as test construction, computer-based assessment, feedback options, large-scale assessment of competencies, and the implementation of assessment tools in school contexts are addressed. Contents: (A) Theoretical perspectives and developmental models. (1) E. Klieme, J. Hartig, and D. Rauch: The concept of competence in educational contexts. (2) M. Hasselhorn: Competencies for successful learning: Developmental changes and constraints. (3) C. Spiel and J. Glueck: A model-based test of competence profile and competence level in deductive reasoning. (B) Psychometric modeling. (4) J. Hartig: Psychometric models for the assessment of competencies. (5) M. Wilson, P. de Boeck, and C. H. Carstensen: Explanatory item response models: A brief introduction. (6) A. A. von Davier, C. H. Carstensen, and M. von Davier: Linking competencies in horizontal, vertical, and longitudinal settings and measuring growth. (7) M. von Davier, L. DiBello, and K. Yamamoto: Reporting test outcomes using models for cognitive diagnosis. (C) Assessment methods and technology. (8) D. Leutner, J. Hartig, and N. Jude: Measuring competencies: Introduction to concepts and questions of assessment in education. (9) A. Jurecka: Introduction to the computer-based assessment of competencies. (10) T. J. H. M. Eggen: Adaptive testing and item banking. (11) J. Wirth: Computer-based tests: Alternatives for test and item design. (12) G. K. W. K. Chung, H. F. O'Neil, W. L. Bewley, and E. L. Baker: Computer-based assessment in support of distance learning. (D) Large-scale assessment for the monitoring of educational quality. (13) T. Seidel and M. Prenzel: Assessment in large-scale studies. (14) E. Klieme and K. Maag Merki: Introduction of educational standards in German-speaking countries. (15) C. Nachtigall, U. Kroehne, U. Enders, and R. Steyer: Causal effects and fair comparison: Considering the influence of context variables on student competencies. (16) I. Hosenfeld: Monitoring and assurance of school quality: Principles of assessment and Internet-based feedback of test results.