Interpreting the WIC debate.

Discusses the efficacy of the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) on pregnancy and birth outcomes. Information on potential effects of nutritional and other health interventions on preterm births; Discussion on a tradeoff between under-controlling for maternal characteristics that may affect both birth outcomes and WIC enrollment; Report that intertrial differences in the subjects analyzed may lead to different estimates of treatment effects on different populations.