The process of Impact Assessment (IA) aims to improve the effectiveness and efficiency of regulation by providing policy makers with information on likely costs and benefits, stimulating early interdepartmental coordination, and promoting stakeholder involvement. The objective is to enable decision-makers to choose the policy option with the greatest benefits at lowest costs, broadly defined. When first introduced, Impact Assessment procedures focused on the economic impacts of regulations. Later on, a number of countries developed other procedures to assess impacts on a wider range of issues such as the environment, social issues, gender, small and medium sized enterprises.The EVIA project carried out comparative case studies and surveys of practitioners to evaluate IA systems. Case studies have been selected from IAs that have been conducted by the European Commission between 2003 and 2005, and from recent IAs in the EU Member States. These include countries that have a long experience in IA, as well as those that have recently introduced IA systems or revised them.The objectives of the project have been achieved in four work packages:- WP1: Developing a Framework of Analysis- WP2: Case Studies and the European Observatory on Impact Assessment- WP3: Practitioner Survey- WP4: Integration and DisseminationKey Outputs:- a database of institutions for IA - the European Observatory on Impact Assessment- a comparative analysis of approaches to IA, with the result that there is a heterogeneity of IA system in the European Union. It is not clear whether the model of integrated assessment of the European Union dominates since many IA systems in Member States only focus on administrative costs.   - a handbook of Impact Assessment including an overview of recent developments and the rules and standards for good practice in integrated impact assessment.The main role of ZEW has been to co-ordinate the survey in WP 3.