Policy Impact Assessments (IAs) are formal, evidence-based procedures that assess the economic, social, and environmental effects of public policy. They have been incorporated into policy making in the OECD countries and the European Commission. Key types of impact assessments include global assessments (global level), policy impact assessment (policy level), strategic environmental assessment (programme and plan level), and environmental impact assessment (project level). Impact assessments can focus on specific themes, such as social impact assessments and gender impact assessments. IAs can improve legislation by:
* Informing policy makers about potential economic, social, and environmental ramifications
* Improving transparency so that contributions to sustainability and "better regulation" are disclosed and special interest lobbying is discouraged
* Increasing public participation in order to reflect a range of considerations, thereby improving the legitimacy of policies
* Clarifying how public policy helps achieve its goals and priorities through policy indicators
* Contributing to continuous learning in policy development by identifying causalities that inform ex-post review of policies
