Classical vs Bayesian Approaches to Modeling Overdispersed Count Data: Case Study of Tomato Leaf Curl


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Authors

  • Briefully Kharnongrum North Eastern Hill University, Shillong
  • Kimthianngak North Eastern Hill University, Shillong
  • Nidahamteinsar Papang North Eastern Hill University, Shillong
  • Priti Pradhan North Eastern Hill University, Shillong
  • Biwash Gurung G.D. Goenka University, Gurugram
  • Ramnunpuia North Eastern Hill University, Shillong

Keywords:

Count data models; Poisson model; Negative Binomial model; Classical estimation; Bayesian estimation; Markov Chain Monte Carlo (MCMC); Over dispersion; Tomato Leaf Curl (TLC); Leave-One-Out Cross-Validation (LOO-CV).

Abstract

Count data consisting of non-negative integer values arising from counting events require specific statistical methods for analysis. This study compares 
Classical and Bayesian approaches for estimating count regression models using Tomato Leaf Curl (TLC) data consisting of 809 observations. 
It is found that the simple Poisson regression model performs poorly due to over dispersion, where the variance greatly exceeds the mean. The 
Negative Binomial model, which handles over dispersion, provides a good fit to the data under both approaches. Both frameworks produced nearly 
the same parameter estimates confirming the consistency of the results. However, the Bayesian framework provided a full posterior distributions 
enables posterior predictive checks supports Leave-One-Out Cross-Validation (LOO-CV) model comparison, providing a richer inferential tool for 
uncertainty. Zero-inflated Poisson model is also used for count data modelling but it is not applicable here due to the absence of zero counts in the 
data. Overall, the Bayesian framework provides a broader view of uncertainty around the estimates.

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Published

2026-11-03

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Articles

How to Cite

Briefully Kharnongrum, Kimthianngak, Nidahamteinsar Papang, Priti Pradhan, Biwash Gurung, & Ramnunpuia. (2026). Classical vs Bayesian Approaches to Modeling Overdispersed Count Data: Case Study of Tomato Leaf Curl. Journal of the Indian Society of Agricultural Statistics, 80(3), 411-418. https://epubs.icar.org.in/index.php/JISAS/article/view/185691