| 1. |
- Sjolander, A, et al.
(författare)
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A GENERAL AND ROBUST ESTIMATION METHOD FOR THE CASE-TIME-CONTROL DESIGN
- 2019
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Ingår i: SOCIOLOGICAL METHODOLOGY, VOL 49. - : SAGE Publications. - 0081-1750. ; 49, s. 349-365
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The case-time-control design is a tool to control for measured, time-varying covariates that increase montonically in time within each subject while also controlling for all unmeasured covariates that are constant within each subject across time. Until recently, the design was restricted to data with only two timepoints and a single binary covariate, or data with a binary exposure. Sjölander (2017) made an important extension that allows for an arbitrary number of timepoints and covariates and a nonbinary exposure. However, his estimation method requires fairly strong model assumptions, and it may create bias if these assumptions are violated. We propose a novel estimation method for the case-time-control design, which to a large extent relaxes the model assumptions in Sjölander. We show in simulations that this estimation method performs well under a range of scenarios and gives consistent estimates when Sjölander’s estimation does not.
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| 2. |
- Sjolander, A, et al.
(författare)
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THE CASE-TIME-CONTROL METHOD FOR NONBINARY EXPOSURES
- 2017
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Ingår i: SOCIOLOGICAL METHODOLOGY, VOL 47. - : SAGE Publications. - 0081-1750. ; 47, s. 182-211
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A popular way to reduce confounding in observational studies is to use each study participant as his or her own control. This is possible when both the exposure and the outcome are time varying and have been measured at several time points for each individual. The case-time-control method is a special case, which, under certain assumptions, allows the analyst to control for confounding by time-varying covariates, while controlling for all time-stationary characteristics of the study participants. There are two formulations of the case-time-control method. One formulation requires that the exposure be binary, and the other requires that there be no more than two time points per individual. In this article the author proposes a generalization of the case-time-control method for nonbinary exposures and an arbitrary number of time points. The author derives the asymptotic properties of the resulting estimator and assesses its finite sample properties in a simulation study.
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