In the context of a broader debate about the future of development evaluation, a discussion has begun on whether it is time to re-think the so called “big five” – the DAC evaluation criteria of relevance, effectiveness, efficiency, impact and sustainability. These criteria underpin most evaluations in international development and have broad practical use far beyond the membership of the network. This note outlines the background, the changing development context and suggests some issues for discussion at the 21st EvalNet meeting.