[KSCI] Korea Science Citation Index Service

http://dx.doi.org/10.5351/CKSS.2012.19.6.761

Modelling Count Responses with Overdispersion

Jeong, Kwang Mo (Department of Statistics, Pusan National University)

Publication Information

Communications for Statistical Applications and Methods / v.19, no.6, 2012 , pp. 761-770 More about this Journal

Abstract

We frequently encounter outcomes of count that have extra variation. This paper considers several alternative models for overdispersed count responses such as a quasi-Poisson model, zero-inflated Poisson model and a negative binomial model with a special focus on a generalized linear mixed model. We also explain various goodness-of-fit criteria by discussing their appropriateness of applicability and cautions on misuses according to the patterns of response categories. The overdispersion models for counts data have been explained through two examples with different response patterns.

Keywords

Clustered data; overdispersion; quasi-likelihood; dispersion parameter; zero-inflated Poisson; negative binomial; generalized linear mixed model;

Citations & Related Records

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