The overall objective of this article is to discuss current theoretical debates in the evaluation literature to assess their relevance for agriculture. After noting the ‘bad press’ of monitoring and evaluation (M&E) in agriculture, the literature is selectively reviewed to see what light is shed from different evaluation paradigms and methodologies. Experiences in the health sector are then examined in greater depth, emphasising debates around randomised controlled trials (RCTs). The final section considers some possible ways forward.