ABSTRACT
Epidemiologic findings may be factual, biased, and driven by a confounding or effect measure modifier. The disentanglement of these spiders in the web of evidence appraisal renders such studies valid and reliable. We often conceive epidemiology in either simplistic or complex terms, and neither of these is an accurate characterization of epidemiologic studies. To illustrate this, complexities in epidemiology could be observed by considering a study to determine the correlation between exposure to allergens and immunoglobulin G (IgG) concentration in children. Two laboratories measured IgG concentration and one observed a correlation while the other did not. Which is the reliable finding? To address this question, one needs to examine the timing of the blood drawing following exposure to an allergen.
