Using longitudinal survey data collected in collaboration with a treatment program, this paper estimates the economic impacts of antiretroviral treatment. The responses in two outcomes are studied: (1) labor supply of treated adult AIDS patients; and (2) labor supply of individuals in...

Not all policy questions can be addressed by social experiments. Nonexperimental evaluation methods provide an alternative to experimental designs but their results depend on untestable assumptions. This paper presents evidence on the reliability of propensity score matching (PSM), which...

This study uses longitudinal data from South Africa to estimate the relationship between early childhood nutritional status and schooling outcomes five years later. Preferred estimates from the full sample aged zero to five, which treat prior nutritional status as endogenous, show no impact of...