In the pages that follow, we shall address these questions regarding the impacts of agencies that work in or on conflict. We shall begin, in Sections II and III, by describing two collaborative efforts undertaken by agencies to learn more about their impacts on conflict within the societies where they work. The first, the Local Capacities for Peace Project (LCCP), involves a number of humanitarian and development assistance agencies seeking to understand how their efforts to save lives, alleviate suffering and support indigenous development interact with, and in some cases reinforce, inter-group conflicts in areas where they provide aid. The second project, Reflecting on Peace Practice (RPP), involves a number of agencies that specifically work on conflict; that is, those agencies that undertake inter-group mediation, reconciliation, peace education, conflict management, conflict transformation and other approaches to reducing the dangers of conflict. In these sections we describe the background, approaches and outcomes of these two projects. In Section IV, we turn to a review of what has been learned through LCCP about how to assess the impacts of humanitarian and development programmes on conflict and, in Section V, we present the findings about how to assess outcomes of efforts intended to reduce conflict and build peace. Finally, in Section VI, we discuss the similarities and differences in assessment techniques required, depending on whether one is working in conflict or on conflict.