Biases in randomized trials: a conversation between trialists and epidemiologists

By Mohammad Ali Mansournia, Julian P. T. Higgins, J. Sterne, Miguel A. Hern'an. 2017

241 citations recorded by the source corpus.

Trialists and epidemiologists often employ different terminology to refer to biases in randomized trials and observational studies, even though many biases have a similar structure in both types of study. We use causal diagrams to represent the structure of biases, as described by the Cochrane Collaboration for randomized trials, and provide a translation to the usual epidemiologic terms of confounding, selection bias, and measurement bias. This structural approach clarifies that an explicit description of the inferential goal—the intention-to-treat effect or the per-protocol effect—is necessary to assess risk of bias in the estimates. Being aware of each other's terminologies will enhance communication between trialists and epidemiologists when considering key concepts and methods for causal inference.

Subfields: Economics and Econometrics, Statistics and Probability

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Citations in the corpus

Handling time varying confounding in observational research (2017, background): “2 12-14 The absence of an arrow pointing from one variable to another indicates that the former does not have a direct causal effect on the latter.”
For and Against Methodologies: Some Perspectives on Recent Causal and Statistical Inference Debates (2017, background): “Randomized trials are indeed a problematic gold standard in practice (Broadbent et al. 2016; Maldonado 2016; Mansournia et al. 2017): Not only do they typically suffer from internal problems and often severe imprecision, but also, due to eligibility restrictions, tend to have more severe generalizab”
RoB 2: a revised tool for assessing risk of bias in randomised trials (2019, methodology): “We label the domains using descriptions of the causes of bias addressed, avoiding terms used in the original RoB tool (such as ‘selection bias’ and ‘performance bias’) because they are used inconsistently or not known by many people outside Cochrane.(16) Each domain is mandatory, and no others can b”