This Working Paper is part of the Transitions in Early Childhood series, published by the Bernard van Leer Foundation and based on data from Young Lives, a 15 year longitudinal study of children growing up in poverty in Ethiopia, India, Peru and Vietnam. In each country, the study tracks approximately 2000 children from infancy to their late teenage years, as well as a comparison cohort of 1000 children, who were first surveyed when they were eight.