The book Infant Mortality: Results of a Field Study in Johnstown, PA., Based on Births in One Calendar Year (1915), written by Emma Duke, detailed one of the first infant mortality field studies conducted by the US Children's Bureau. In the study, Duke and her colleagues collected information about over one thousand infants in the city of Johnstown, Pennsylvania. They used that information, along with interviews conducted with the families of the infants, to identify factors that affected infant mortality rates in the community. Duke and her team found strong correlations between elevated infant mortality rates and conditions experienced by Johnstown residents of lower socioeconomic status. The design and implementation of the study described in Infant Mortality: Johnstown, PA provided a model for future Children's Bureau research that resulted in seven additional infant mortality studies in other US cities. Infant Mortality: Results of a Field Study in Johnstown, PA., Based on Births in One Calendar Year quantitatively demonstrated the link between poverty and infant mortality.