Visualizing a three-dimensional relation among an exposure, an outcome, and a third factor is complicated, particularly when students are first being introduced to epidemiologic methods. The heuristic device described below can be used by teachers of epidemiology to help introductory students understand how a third factor will affect the association between an exposure and an outcome. The devic...

Abstract The epidemiologist Bradford Hill famously argued that in epidemiology, specificity of association (roughly, the fact an environmental or behavioral risk factor is associated with just one at most a few medical outcomes) strong evidence causation. Prominent epidemiologists have dismissed Hill’s claim on ground it relies dubious `one-cause effect’ model disease paper examines this method...

Environmental epidemiology comprises the epidemiologic study of those environmental factors that are outside the immediate control of the individual. Exposures of interest to environmental epidemiologists include air pollution, water pollution, occupational exposure to physical and chemical agents, as well as psychosocial elements of environmental concern. The main methodologic problem in envir...

Studies in air pollution epidemiology may suffer from some specific forms of confounding and exposure measurement error. This contribution discusses these, mostly in the framework of cohort studies. Evaluation of potential confounding is critical in studies of the health effects of air pollution. The association between long-term exposure to ambient air pollution and mortality has been investig...

Stool samples from 880 residents in an urban slum in Dhaka, Bangladesh, were collected on 3 occasions over one year, and examined for intestinal parasites. Information on many potential risk factors for infection was obtained by questionnaire from a respondent in each household studied. In a crude univariate analysis of the data, several of the factors were found to be significantly associated ...

This article discusses the importance, definition, and types of confounders in epidemiology. Methods to identify and address confounding are discussed, as well as their strengths and limitations. The article also describes the difference among confounders, mediators, and effect modifiers.

In social epidemiology, an individual's neighborhood is considered to be an important determinant of health behaviors, mediators, and outcomes. Consequently, when investigating health disparities, researchers may wish to adjust for confounding by unmeasured neighborhood factors, such as local availability of health facilities or cultural predispositions. With a simple random sample and a binary...

Although much has been written on this subject, there still seems to be considerable confusion in the literature concerning dissociations, double dissociations and what they really mean, especially when connectionist or neural network models are involved. In this paper I attempt to clarify matters by looking at the subject from the point of view of patterns of learning rates in neural network m...

Since confounding obscures the real effect of the exposure, it is important to adequately address confounding for making valid causal inferences from observational data. Directed acyclic graphs (DAGs) are visual representations of causal assumptions that are increasingly used in modern epidemiology. They can help to identify the presence of confounding for the causal question at hand. This stru...