Effect Modification and Interaction Terms: It Takes Two to Tango.
In this Investigators' Corner I look more deeply into the previously discussed phenomenon of effect modification. I revisit an explanation and examples of the phenomenon and then examine how to account for it statistically. Specifically, I show, in detail, how to write a regression equation that includes interaction terms that account for the effect modification. Finally, I look at interpretation of regression coefficients both with and without the presence of effect modification, and the associated interaction terms.
Assistant Professor, Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, TX. Electronic address: dajupiter@utmb.edu.
Daniel C
DC
Jupiter
D015984:Causality; D015986:Confounding Factors, Epidemiologic; D003627:Data Interpretation, Statistical; D016021:Epidemiologic Studies; D006801:Humans; D015999:Multivariate Analysis; D012044:Regression Analysis; D012680:Sensitivity and Specificity
confounding; effect modification; interaction terms; multivariate analysis; regression