Spillovers without Social Interactions in Urban Sanitation

Abstract

We run a randomized controlled trial coupled with lab-in-the-field social network experiments in urban Dakar. Decision spillovers and health externalities play a large role in determining uptake of sanitation technology, with decision spillovers being largest among households that don’t receive significant subsidies. There is no evidence that social mechanisms such as social pressure, learning from others, or reciprocity explain the spillovers. We do find evidence of a fourth, non-social, mechanism impacting decisions: increasing returns to scale. As more neighbors adopt the sanitary technology, it becomes more worthwhile for other households to adopt as well.