1. Cesar Gomes Victora, Gary Joseph, Inacio C. M. Silva, and Aluisio J. D. Barros are with the International Center for Equity in Health, Federal University of Pelotas, Pelotas, Brazil. Fatima S. Maia is with the Federal University of Rio Grande (FURG), Rio Grande, Brazil. J. Patrick Vaughan is with the Health Policy Unit, London School of Hygiene and Tropical Medicine, London, United Kingdom. Fernando C. Barros is with Post Graduate Course in Health and Behavior, Catholic University of Pelotas, Pelotas.