What difference are we making? How do we know? These are the most basic questions one can ask about the impact of an emergency project. Yet too often questions that help identify whats working and whats not go unasked in the course of an emergency response. They are left instead to evaluators. As a result, questions which could–literally–save lives are asked only after a crisis is over. At a workshop conducted in Nairobi in 2006, Emergency Capacity Building project members defined what impact measurement and accountability meant for them and pledged to try a quick and simple good enough approach when putting their ideas into practice in the field. This pocket book is the result. The good enough approach favors simple solutions over elaborate ones and encourages the user to choose tools that are safe, essential, quick, and simple to implement. This guide outlines the basic principles of impact measurement and accountability in relation to humanitarian response and suggests some tried and tested easy-to-implement tools for putting these principles into practice from the beginning of a project. It offers practical wisdom for the busy fieldworker on how to be accountable to local people and measure program impact in an emergency. This practical guide is aimed at humanitarian practitioners, project officers, and managers with some experience in the field, and draws on the work of individual NGOs and inter-agency initiatives, including Sphere, ALNAP, HAP International, and People In Aid. Members of the Emergency Capacity Building Project are CARE International, Catholic Relief Services, the International Rescue Committee, Mercy Corps, Oxfam GB, Save the Children-USA, and World Vision International.