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Review
. 2016 Nov:79:70-75.
doi: 10.1016/j.jclinepi.2016.04.014. Epub 2016 May 27.

Specifying a target trial prevents immortal time bias and other self-inflicted injuries in observational analyses

Miguel A Hernán  1 , Brian C Sauer  2 , Sonia Hernández-Díaz  3 , Robert Platt  4 , Ian Shrier  5
Affiliations
Review

Specifying a target trial prevents immortal time bias and other self-inflicted injuries in observational analyses

Miguel A Hernán et al. J Clin Epidemiol. 2016 Nov.

Abstract

Many analyses of observational data are attempts to emulate a target trial. The emulation of the target trial may fail when researchers deviate from simple principles that guide the design and analysis of randomized experiments. We review a framework to describe and prevent biases, including immortal time bias, that result from a failure to align start of follow-up, specification of eligibility, and treatment assignment. We review some analytic approaches to avoid these problems in comparative effectiveness or safety research.

Keywords: Comparative effectiveness research; Immortal time bias; Observational; Selection bias; Target trial; Time zero; studies.

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Figures

Fig. 1
Fig. 1
Four examples of failures of emulation of a target trial using observational data. T0, time zero; E, eligibility; A, period during which treatment strategies are assigned.
See this image and copyright information in PMC

References

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