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Covariate measurement error in generalized linear models for longitudinal data: a latent Markov approach
Last modified: 2018-05-18
Abstract
One common approach to handle covariate measurement error in Generalized Linear Models is
classical error modeling. In the past 20 years, classical error modeling has been brought
to (Non-Parametric) Maximum Likelihood (ML) estimation, by means of finite mixture modeling:
the supposedly continuous true score is modeled as a multinomial static latent variable and is
handled as a part of the model. Nonetheless, the true score is not allowed to vary over time:
if the true score has own underlying dynamics, these are either unaccounted for or mistaken for
measurement error, or possibly both. The present paper formulates a joint model
for the outcome variable, the covariate observed with error, and the
true score, accounting for its underlying dynamics by assuming a first-order latent Markov chain.
From an applied researcher perspective, this methodology can safely handle both the case where the
underlying characteristic is stable over time, as well as providing a suitable framework even when
changes across measurement occasions are substantial, with estimation done within a familiar ML
environment. It is demonstrated, by means of extensive simulation studies and a real-data
application, that the methodology delivers correct estimates of the model parameters of interest,
as well as good coverages.
classical error modeling. In the past 20 years, classical error modeling has been brought
to (Non-Parametric) Maximum Likelihood (ML) estimation, by means of finite mixture modeling:
the supposedly continuous true score is modeled as a multinomial static latent variable and is
handled as a part of the model. Nonetheless, the true score is not allowed to vary over time:
if the true score has own underlying dynamics, these are either unaccounted for or mistaken for
measurement error, or possibly both. The present paper formulates a joint model
for the outcome variable, the covariate observed with error, and the
true score, accounting for its underlying dynamics by assuming a first-order latent Markov chain.
From an applied researcher perspective, this methodology can safely handle both the case where the
underlying characteristic is stable over time, as well as providing a suitable framework even when
changes across measurement occasions are substantial, with estimation done within a familiar ML
environment. It is demonstrated, by means of extensive simulation studies and a real-data
application, that the methodology delivers correct estimates of the model parameters of interest,
as well as good coverages.
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