Infodemiology: The Epidemiology of (Mis)information

and other variables are related (Figure), are more useful in addressing questions such as "Are government sites more accurate than commercial sites?" or "Are websites that disclose the authorship and include a date of last update more accurate?" One important question is which markers or characteristics of a website are "valid" quality criteria to discriminate or predict a "good" health website. A valid quality criterion would be a feature (or a combination of features) that predicts effective health communication in terms of improving knowledge or changing health behavior, or which is associated with a measurable effect on health outcomes. However, analyses of site characteristics and health outcomes can be complicated, since measuring the very small and indirect effect that a single site may have on health outcomes is not feasible. Furthermore, users rarely use only one website and often use other sources of information, and health outcomes may take years to develop. Perhaps a more