Title
The impact of misspecification of nuisance parameters on test for homogeneity in zero-inflated Poisson model: A simulation study
Abstract
Most of the existing methodologies for evaluating heterogeneity in zero-inflated Poisson (ZIP) models are often assuming that the Poisson mean is a function of nuisance parameters. However, these nuisance parameters can be misspecified when performing these methodologies, the validity and the power of the test may be affected. In this article, we primarily focus on investigating the impact of misspecification on the performance of score test for homogeneity in ZIP models. Through an intensive simulation study, we find that: 1) under misspecification, the limiting distribution of the score test statistic under the null no longer follows a distribution. A parametric bootstrap methodology is suggested to use to find the true null limiting distribution of the score test statistic; 2) the power of the test decreases as the number of covariates in the Poisson mean increases. The test with a constant Poisson mean has the highest power, even compared to the test with a well-specified mean. At last, simulation results are applied to the Wuhan Inpatient Care Insurance data which contain excess zeros.
Year
DOI
Venue
2022
10.1080/03610918.2019.1646758
COMMUNICATIONS IN STATISTICS-SIMULATION AND COMPUTATION
Keywords
DocType
Volume
Zero-inflated Poisson model, Score test, Misspecification, Nuisance parameter
Journal
51
Issue
ISSN
Citations 
1
0361-0918
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Siyu Gao100.34
Qianqian Zhang200.34
Jing Yu300.34