Chapter 2 details how Karl Pearson’s mathematical statistics were integrated into public health education, specifically at the Johns Hopkins School of Public Health (JHSPH) statistics department and its Chinese counterpart at the Peking Union Medical College (PUMC) in Beijing. Conceptions of the role of statistics in science differed at the two schools: the JHSPH aspired to identify the underlying statistical regularities in life and death; the PUMC was focused on testing and adapting scientific knowledge to fit Chinese public health work. The JHSPH’s transition from a biological focus in Pearson’s tradition to a focus on public health and epidemiology is also discussed. That approach was transferred – up to a point – to the PUMC. The major intermediaries in the transfer were a JHSPH alumnus and Rockefeller Foundation officer, John B. Grant, and one of his students, Yuan Yijing. Graduates of the two schools went on to use mathematical statistics in fieldwork, though they encountered resistance from locals and other experts. Statistical reporting nonetheless gained an increasingly prominent role in public health work in New York, Geneva, and Beijing. Graduates of the two schools were later employed by health organizations at different levels.