A Poisson Regression Model For Analysis of Censored Count Data with Excess Zeroes

Seyed Ehsan Saffari, Robiah Adnan, William Greene, Maizah Hura Ahmad

Abstract


Typically, a Poisson regression model is assumed for count data. In many cases, there are many zeros in the dependent variable, therefore the mean is not equal to the variance value of the dependent variable. Thus, we suggest using a hurdle and zero-inflated Poisson regression model. Furthermore, the response variable in such cases is censored for some values. In this paper, a censored hurdle Poisson regression model and a censored zero-inflated Poisson regression model will be discussed to handle the overdispersion problem when there are excess zeros in the response variable. The estimation of regression parameters using the maximum likelihood method is discussed and the goodness-of-fit statistics for the regression model are examined. An example and a simulation will be used to compare the censored hurdle Poisson regression model with the censored zero-inflated Poisson regression model in terms of the parameter estimation, standard errors and the goodness-of-fit statistics.


Keywords


Censored model; Poisson regression; overdispersion; excess zeros

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References


Caudill, S. B. and Mixon Jr., F. G. 1995. Modeling Household Fertility Decisions: Estimation and Testing of Censored Regression Models for Count Data. Empirical Economics. 20(2): 183–197.

. Greene, W. 2007. Functional Form and Heterogeneity in Models for Count Data. Foundations and Trends in Econnometrics. 1(2): 113–218.

. Gurmu, S. 1998. Generalized Hurdle Count Data Regression Models. Economics Letters. 58: 263–268.

. Lambert, P. J. 1989. The Distribution and Redistribution of Income - A Mathematical Analysis. Oxford, U.K.: Basil Blackwell.

. Lambert, P. J. 1992. Zero-Inflated Poisson Regression, with an Application to Defects in Manufacturing. Technometrics. 34(1): 1–14.

. Mullahy, J. 1986. Specication and Testing of some Modified Count Data Models. Journal of Econometrics. 33: 341–365.

. Terza, J. V. 1985. A Tobit-Type Estimator for the Censored Poisson Regression Model. Economics Letters. 18: 361–365.




DOI: https://doi.org/10.11113/jt.v63.1915

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