Heterogeneous impact of the social programme Oportunidades on use of contraceptive methods by young adult women living in rural areas

Rarely have researchers explored the distribution of a programme's effects in a population, tending to focus on unidimensional measures of impact instead. This can mask heterogeneity of effects, making it difficult to identify subsets of the population for whom impacts might differ from a population average. The authors exploit the design of Mexico's Oportunidades programme to construct measures of the heterogeneous impacts of the programme on contraception and compare these with conventional effect estimates. They find that the latter, while probably reliable for particular types of effects, fail to uncover the substantial programme impacts on the poorest women in rural Mexico.