Health systems research generates new knowledge to improve health service provision. The notion that simple solutions to health systems problems are waiting to be discovered relies on the idea that those implementing policy are ‘robots’ (that do whatever they are told) or ‘angels’ (that always serve the greater good). In contrast, Professor McPake will show how effective health systems research in low income countries is based on the idea that implementers are human beings who respond to incentives and social and psychological features of their environment.