village, schools, health centres). Many interventions are implemented for example at the community/village level, with the expected benefits also to be captured at that level, requiring village- instead of individual-based randomisation. The other reason for a clustered approach is the large expected spillovers within tightly knit rural communities, which would entail that other individuals within a community where some members are participating in a programme may also benefit from the intervention (e.g. by watching their neighbours and talking to them). 3ie is funding four ongoing impact evaluations focusing on promoting latrine use among rural households in four different states in India. As all four projects are complex interventions involving social demonstrations, workshops, community events and mixed-media communication, there is a high risk of spillover effects of the interventions among individuals and households in the treatment areas. As a result, all four projects have taken a clustered RCT approach in order to avoid these effects.