Title

Bayesian Inference for Skew-Normal Mixture Models With Left-Censoring

Document Type

Article

Publication Date

2013

Keywords

Bayesian inference, Censoring, Mixed-effects models, Skew-normal distribution, Tobit model

Digital Object Identifier (DOI)

https://doi.org/10.1080/10543406.2013.813517

Abstract

Assays to measure concentration of antibody after vaccination are often subject to left-censoring due to a lower detection limit (LDL), leading to a high proportion of observations below the detection limit. Not accounting for such left-censoring appropriately can lead to biased parameter estimates. To properly adjust for left-censoring and a high proportion of observations at LDL, this article proposes a mixture model combining a point mass below LDL and a Tobit model with skew-elliptical error distribution. We show that skew-elliptical distributions, where the skew-normal and skew-t are special cases, have great flexibility for simultaneously handling left-censoring, skewness, and heaviness in the tails of a distribution of a response variable with left-censored data. A Bayesian procedure is used to estimate model parameters. Two real data sets from a study of the measles vaccine and an HIV/AIDS study are used to illustrate the proposed models.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Journal of Biopharmaceutical Statistics, v. 23, issue 5, p. 1023-1041

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