How did John Snow impact epidemiology?

How did John Snow impact epidemiology?

Robert Friis (Chair, Health Sciences Department, California State University, Long Beach ) gives expert video advice on: How did John Snow impact epidemiology?; How did John Graunt change epidemiology? and more...

John Snow impacted epidemiology by devising the method that is known as a natural experiment. This method is used today in current epidemiologic research. For example, John Snow used a spot map to show the occurrence of disease and that technique is used in contemporary epidemiology. And he had many other innovations that he developed in his study of the London and Soho outbreak that are used today.