Impact Assessment (IA) is introduced in this book, with a guide to the process, scope, content, and management of IA for the governments of developing economies. In doing so, evidence-based policy making is taken into full consideration.  After the principles of IA are set forth, its procedures are described,  illustrated by typical cases from the United States and Japan. Then an explanation follows of the components of IA such as necessity, alternatives, and assessment of cost and benefit, with a description of competition assessment. In developing economies,  it is not effective to simply import a system from developed countries directly into developing countries, especially for economic regulation and in consideration of compliance and competition issues. Thus the book provides recommendations on how to appropriately modify developed countries’ systems for countries that are still developing. The book concludes by taking up several issues surrounding IA, especiallynudge theory and public involvement.