The European Commission requires an impact assessment report for any regulation proposed. This book analyzes the quality of impact assessments and discusses deficits and possible improvements. Based on 30 case studies of impact assessments, an institutional analysis of the relevant actors is conducted, which shows that there are many shortcomings, among them an incentive problem concerning desk officers in the European Commission. The book includes various articles which address controversial problems and possible solutions. It offers a comprehensive overview of the practice of impact assessment in the EC, as well as an institutional analysis of the processes involved and of the checks and balances between politicians and their administration.