Epidemiology is the study of the patterns, causes, and effects of health and disease conditions in defined populations. Epidemiology’s main role is preventing the onset and spread of disease by finding the reasons why some groups of people are healthier than others and then removing or controlling these causes.
A career as an epidemiologist usually prefer at least a master's degree in epidemiology. Increasingly, however, undergraduate students can obtain employment in state and local governments and other settings; yet most seek specialized training in epidemiology in schools of public health. Epidemiology is a basic science of public health.