Sustainability is one of five evaluation criteria used by the Organisation of Economic Development Cooperation (OECD). The other four are coherence, relevance, efficiency, impact, and effectiveness. The OECD Development Assistance Committee Network on Development Evaluation defines sustainability as “the extent to which the net benefits of the intervention continue, or are likely to continue.” In simpler terms, the main question under sustainability is “will the benefits last?”.
Definition adapted from OECD/DAC Network on Development Evaluation (2019):“Better Criteria for Better Evaluations. Revised Evaluation Criteria. Definitions and Principles for Use”.