Driven by more complex and complicated policy challenges, persistent problems, and conflicting interests, the desire for rooting policy-making in the available stock of knowledge and applying supporting techniques and procedures has grown. Impact Assessments (IA) are increasingly promoted and implemented in recent years at the European Union (EU) level and in member states. They are understood as attempts, procedures and tools to assess, usually ex ante, the effects of policies on the physical and societal environment, notably on the dimensions of sustainable development.