A positive or a negative confounding variable? A simple teaching aid for clinicians and students.
Anticipating the direction of a confounding variable can be problematic especially to introductory students. Using elementary rules of mathematics, we describe below a simple instructional tool for deriving the direction of confounding bias. The tool is illustrated with examples and a heuristic mathematical justification is also described.
Mehio-Sibai
Abla
A
Department of Epidemiology and Population Health, Faculty of Health Sciences, American University of Beirut, Beirut, Lebanon. ansibai@aub.edu.lb
Feinleib
Manning
M
Sibai
Tarek A
TA
Armenian
Haroutune K
HK
D015982:Bias; D015986:Confounding Factors, Epidemiologic; D004813:Epidemiology / Q000193:education*; D007861:Lebanon; D015233:Models, Statistical; D010820:Physicians; D013337:Students, Medical