Regression

Many analyses of epidemiologic data are conducted using statistical methods common to other research [Page 899]fields, including the social and biologic sciences. In epidemiologic studies, however, the focus of the research question, and thus the methods used to study this question, tend to differ. The combination of human, social, environmental, and biological factors that may be present in epidemiologic studies can lead to a complexity not seen in large randomized trials or when the environment can be controlled. This entry discusses regression methods used in epidemiology and the conceptual framework that underlies these methods.