title: Effect modification in epidemiology and medicine.
abstract: Effect modification, also known as interaction or heterogeneity of effect, is an important concept in epidemiology.  This article reviews the definition and types of effect modification, methods to detect effect modification, the reasons for observing effect modification in epidemiologic studies, the importance of choice of model in finding effect modifiers, and effect modifications that are important to public health.
authors.affiliation: School of Community Health and Policy, Morgan State University, Baltimore, MD 21251, USA. farin.kamangar@morgan.edu
authors.forename: Farin
authors.initials: F
authors.lastname: Kamangar
mesh_terms: D015986:Confounding Factors, Epidemiologic; D003627:Data Interpretation, Statistical; D015987:Effect Modifier, Epidemiologic; D015340:Epidemiologic Research Design; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D011634:Public Health; D012044:Regression Analysis; D012307:Risk Factors; D018401:Sample Size