This dissertation consists of 3 essays on development economics, with an overarching theme that relates to the economics of the family, child human capital, and migration. The three essays combine rigorous empirical strategies with the use of uniquely rich longitudinal data, the Mexican Family Life Survey, to advance our understanding of individual, household and family behavior. Using these population‐level data, the first chapter is an evaluation of a prominent anti‐poverty program, Oportunidades, on child nutrition. Oportunidades was a leading intervention in targeting resources towards women and linking public transfers to investments in child human capital, and currently serves about one quarter of the Mexican population. To isolate the impact of the program, I draw on evidence from the nutrition and biology literatures regarding the biology of child growth, in combination with the timing of the roll‐out of the program and the panel dimension of the data. Consistent with previous evidence, this analysis finds positive and sizable effects on children who live in rural communities incorporated at the beginning of the intervention. In contrast, the impact of the program in rural localities incorporated later in time and in suburban and urban communities are, at best, very modest. The second chapter uses extensive information on non‐co‐resident family members, and variation in the spatial dispersion among them, to study the extent to which Mexican families share resources across households and test different models of family behavior. I extend previous work by explicitly looking at families with different degrees of spatial dispersion among their members, including families with members spread across international borders. I adapt the collective model developed in the intra‐ household literature to model the family decision problem, and I analyze family behavior with respect to two sets of outcomes: household budget shares and child human capital indicators. The results suggest that the combination of looking at different degrees of spatial dispersion within families and different dimensions of family behavior is crucial to a precise understanding of inter‐household decision‐making.