The objective of this paper is to understand and test empirically the relationship between group size and informal risk sharing. Models of informal risk sharing with limited commitment and grim-trigger punishments upon deviation imply that larger groups provide better informal insurance....

Basic methods to compute the required sample size are well understood and supported by widely available software. However, the sophistication of the sample size methods commonly used has not kept pace with the complexity of the experimental designs most often employed in practice. In this paper,...

We show that children who are born at or just before the weekend are less likely to be breastfed, owing to poorer breastfeeding support services in hospitals at weekends. We use this variation to estimate the effect of breastfeeding on children’s development in the first five years of life,...