Next Article in Journal
A New Burr XII-Weibull-Logarithmic Distribution for Survival and Lifetime Data Analysis: Model, Theory and Applications
Previous Article in Journal
A New Extended Birnbaum–Saunders Model: Properties, Regression and Applications
Article Menu

Export Article

Open AccessArticle
Stats 2018, 1(1), 48-76; https://doi.org/10.3390/stats1010005

The Impact of Misspecified Random Effect Distribution in a Weibull Regression Mixed Model

1
Escuela de Estadística, Universidad Nacional de Colombia sede Medellín, Medellín 050034, Colombia
2
Instituto de Matemática e Estatística, Universidade de São Paulo, São Paulo 05508-090, Brazil
*
Author to whom correspondence should be addressed.
Received: 17 March 2018 / Revised: 25 May 2018 / Accepted: 29 May 2018 / Published: 31 May 2018
Full-Text   |   PDF [599 KB, uploaded 20 July 2018]   |  

Abstract

Mixed models are useful tools for analyzing clustered and longitudinal data. These models assume that random effects are normally distributed. However, this may be unrealistic or restrictive when representing information of the data. Several papers have been published to quantify the impacts of misspecification of the shape of the random effects in mixed models. Notably, these studies primarily concentrated their efforts on models with response variables that have normal, logistic and Poisson distributions, and the results were not conclusive. As such, we investigated the misspecification of the shape of the random effects in a Weibull regression mixed model with random intercepts in the two parameters of the Weibull distribution. Through an extensive simulation study considering six random effect distributions and assuming normality for the random effects in the estimation procedure, we found an impact of misspecification on the estimations of the fixed effects associated with the second parameter σ of the Weibull distribution. Additionally, the variance components of the model were also affected by the misspecification. View Full-Text
Keywords: misspecification; random effects; mixed models; Weibull regression misspecification; random effects; mixed models; Weibull regression
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Hernández, F.; Giampaoli, V. The Impact of Misspecified Random Effect Distribution in a Weibull Regression Mixed Model. Stats 2018, 1, 48-76.

Show more citation formats Show less citations formats

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Stats EISSN 2571-905X Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top