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Structural zeroes and zero-inflated models

SUMMARY: In psychosocial and behavioral studies count outcomes recording the frequencies of the occurrence of some health or behavior outcomes (such as the number of unprotected sexual behaviors during a period of time) often contain a preponderance of zeroes because of the presence of ‘structural z...

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Autores principales: HE, Hua, TANG, Wan, WANG, Wenjuan, CRITS-CHRISTOPH, Paul
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Shanghai Municipal Bureau of Publishing 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4194007/
https://www.ncbi.nlm.nih.gov/pubmed/25317011
http://dx.doi.org/10.3969/j.issn.1002-0829.2014.04.008
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author HE, Hua
TANG, Wan
WANG, Wenjuan
CRITS-CHRISTOPH, Paul
author_facet HE, Hua
TANG, Wan
WANG, Wenjuan
CRITS-CHRISTOPH, Paul
author_sort HE, Hua
collection PubMed
description SUMMARY: In psychosocial and behavioral studies count outcomes recording the frequencies of the occurrence of some health or behavior outcomes (such as the number of unprotected sexual behaviors during a period of time) often contain a preponderance of zeroes because of the presence of ‘structural zeroes’ that occur when some subjects are not at risk for the behavior of interest. Unlike random zeroes (responses that can be greater than zero, but are zero due to sampling variability), structural zeroes are usually very different, both statistically and clinically. False interpretations of results and study findings may result if differences in the two types of zeroes are ignored. However, in practice, the status of the structural zeroes is often not observed and this latent nature complicates the data analysis. In this article, we focus on one model, the zero-inflated Poisson (ZIP) regression model that is commonly used to address zero-inflated data. We first give a brief overview of the issues of structural zeroes and the ZIP model. We then given an illustration of ZIP with data from a study on HIV-risk sexual behaviors among adolescent girls. Sample codes in SAS and Stata are also included to help perform and explain ZIP analyses.
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spelling pubmed-41940072014-10-14 Structural zeroes and zero-inflated models HE, Hua TANG, Wan WANG, Wenjuan CRITS-CHRISTOPH, Paul Shanghai Arch Psychiatry Biostatistics in Psychiatry (22) SUMMARY: In psychosocial and behavioral studies count outcomes recording the frequencies of the occurrence of some health or behavior outcomes (such as the number of unprotected sexual behaviors during a period of time) often contain a preponderance of zeroes because of the presence of ‘structural zeroes’ that occur when some subjects are not at risk for the behavior of interest. Unlike random zeroes (responses that can be greater than zero, but are zero due to sampling variability), structural zeroes are usually very different, both statistically and clinically. False interpretations of results and study findings may result if differences in the two types of zeroes are ignored. However, in practice, the status of the structural zeroes is often not observed and this latent nature complicates the data analysis. In this article, we focus on one model, the zero-inflated Poisson (ZIP) regression model that is commonly used to address zero-inflated data. We first give a brief overview of the issues of structural zeroes and the ZIP model. We then given an illustration of ZIP with data from a study on HIV-risk sexual behaviors among adolescent girls. Sample codes in SAS and Stata are also included to help perform and explain ZIP analyses. Shanghai Municipal Bureau of Publishing 2014-08 /pmc/articles/PMC4194007/ /pubmed/25317011 http://dx.doi.org/10.3969/j.issn.1002-0829.2014.04.008 Text en Copyright © 2014 by Shanghai Municipal Bureau of Publishing http://creativecommons.org/licenses/by-nc-sa/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/4.0/
spellingShingle Biostatistics in Psychiatry (22)
HE, Hua
TANG, Wan
WANG, Wenjuan
CRITS-CHRISTOPH, Paul
Structural zeroes and zero-inflated models
title Structural zeroes and zero-inflated models
title_full Structural zeroes and zero-inflated models
title_fullStr Structural zeroes and zero-inflated models
title_full_unstemmed Structural zeroes and zero-inflated models
title_short Structural zeroes and zero-inflated models
title_sort structural zeroes and zero-inflated models
topic Biostatistics in Psychiatry (22)
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4194007/
https://www.ncbi.nlm.nih.gov/pubmed/25317011
http://dx.doi.org/10.3969/j.issn.1002-0829.2014.04.008
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