This book is a detailed manual for the implementation of competence diagnostics in the field of vocational training. With the COMET competence model, both conceptual competences as well as practical skills are recorded and evaluated. The manual guides through all methodological steps, including the preparation and implementation of tests, cross and longitudinal studies, the development of context analyses and measurement methods for the test motivation. The focus of the final chapter is the application of the COMET procedure for the design, organisation and evaluation of vocational education and training processes.