The Development Assistance Committee (DAC) working party on Aid Evaluation (WP-EV) has developed this glossary of terms in evaluation and results-based management because of the need to clarify concepts and to reduce the terminological confusion frequently encountered in these areas. Evaluation is a field where development partners often with widely differing linguistic backgrounds - work together and need to use a common vocabulary. The selection of terms and their definitions in the attached glossary have been carefully discussed and analysed and have benefited from advice and inputs, notably from DAC Members and the academic evaluation community. A WP-EV Task Force, chaired by the World Bank, led the overall project, in collaboration with the Secretariat. France took the lead on the French version, whilst the Inter-American Development Bank produced the Spanish translation. Denmark, the Netherlands, Norway, and UNDP provided financial support for the initial collection and review work, and Switzerland contributed financial support for producing this free distribution publication.