Ecological bias is sometimes attributed to confounding by the group variable (ie the variable used to define the ecological groups), or to risk factors associated with the group variable. We show that the group variable need not be a confounder (in the strict epidemiological sense) for ecological bias to occur: effect modification can lead to profound ecological bias, whether or not the group v...

Epidemiologists are aware that the estimated effect of an exposure can be biased if the investigator fails to adjust for confounding factors when analyzing either a prospective or retrospective etiologic study. Standard texts warn, however, that intervening factors are an exception: one should not adjust for any factor which is intermediate on the causal pathway between the exposure and the dis...

We identify situations in which conditioning on text can address confounding in observational studies. We argue that a matching approach is particularly well-suited to this task, but existing matching methods are ill-equipped to handle high-dimensional text data. Our proposed solution is to estimate a low-dimensional summary of the text covariates and condition on this summary via matching. We ...

The epidemiological concept of confounding has had a convoluted history. It was first expressed as an issue of group non-comparability, later as an uncontrolled fallacy, then as a controllable fallacy named confounding, and, more recently, as an issue of group non-comparability in the distribution of potential outcome types. This latest development synthesised the apparent disconnect between ph...

According to the authors, time-modified confounding occurs when the causal relation between a time-fixed or time-varying confounder and the treatment or outcome changes over time. A key difference between previously described time-varying confounding and the proposed time-modified confounding is that, in the former, the values of the confounding variable change over time while, in the latter, t...

The objective of DARPA’s Human ID at a Distance (HID) program “is to develop automated biometric identification technologies to detect, recognize and identify humans at great distances.” While nominally intended for security applications, if deployed widely, such technologies could become an enormous privacy threat, making practical the automatic surveillance of individuals on a grand scale. Fa...

STUDY OBJECTIVE To describe the advantages of using Poisson regression methods as an alternative to standardisation when computing expected numbers of disease occurrences adjusted for possible confounding factors. The problem of assessing the adequacy of model fit when the expectations are small is addressed by analytical calculations and by simulation. The method is illustrated with data from ...

In this paper, the issue of the prion hypothesis, a simmering controversy within the scientific community, is addressed. We inquire into the appropriateness of the use of certain augmentations and rhetoric approaches used during scientific debates, as well as the aptness of unequivocal statements in textbooks that indicate "abnormal prions" as a primary cause of Transmissible Spongiform Encepha...

Insular gliomas were previously considered inoperable lesions and were typically treated via biopsy, chemotherapy and/or radiation, if not observation alone. Stereotactic biopsies of low grade insular gliomas can underestimate tumor grade or fail to establish malignancy. Moreover, the survival advantages of maximal safe resection for insular lesions are increasingly being recognized. As such, e...

I Assessing the causal effect of a treatment variable X on an outcome variable Y from observational data is usually difficult due to the possible existence of unobserved common causes. I In our paper we examine how, given an observed dependence between X and Y , various kinds of additional assumptions which related to the “strength” of confounding of X and Y can help to estimate the causal effe...