David Guilkey is a Cary C. Boshamer Distinguished Professor of Economics and is one of the CPC statistical advisors. He is interested in statistical problems associated with large survey data sets. His current work involves both domestic and international data sets. His work in the United States is primarily in collaboration with CPC fellows Barry Poplin and Penny Gordon-Larsen and involves NIH funded research on the impact of physical activity on obesity and ultimately on health using a structural equations modeling approach. His international research is joint with CPC fellows Ilene Speitzer, John Stewart, Sian Curtis, and Gustavo Angeles and is funded by the Bill and Melinda Gates Foundation. This work includes primary data collection where the data will be used to evaluate the Urban Reproductive Health Initiative that is also funded by the Foundation in urban areas of five countries.