This report from the European Centre for the Development of Vocational Training analyzes skill mismatch and its implications for policymaking. It finds that skill mismatch, including overeducation, underskilling, skill shortages, and skills obsolescence, is a significant issue in Europe that impacts individuals, firms, and societies. The report seeks to structure information on skill mismatch and answer key questions to inform evidence-based policy. Specifically, it examines what is known about the different types of skill mismatch in Europe; the causes of mismatch; the relationships between different forms of mismatch; the impact of business cycles and the economic crisis on mismatch; the implications of mismatch for productivity, job satisfaction, and costs; appropriate ways to measure mismatch;