It is striking how little attention is paid to the unintended effects of development cooperation in evaluations thereof, despite the OECD guidelines that stipulate that evaluators should look at these. A recent meta-evaluation of the evaluation quality of the largest bilateral aid agency in the world, USAID, showed that only 15% of it evaluations paid attention to the unintended effects of development cooperation. In the case of the Norwegian Agency for Development Cooperation, NORAD, only 40% of the terms of reference for evaluations requested evaluators to take unintended effects into consideration, which was often done in a superficial way. More and more it is acknowledged that this dearth of (evaluation) research on the unintended effects of international cooperation needs urgent attention. Dirk-Jan Koch, recently appointed Special Professor of International Trade and Development Cooperation at Radboud University, Nijmegen, states that two types of unintended effects – the ignored and the invisible – should be studied much more.