{"doi":"10.3329/ijss.v23i2.70105","title":"Outliers as a Source of Overdispersion in Poisson Regression Modelling: Evidence from Simulation and Real Data","abstract":"<jats:p>The Poisson regression model is a well-known technique for modelling count data. However, it is necessary to satisfy the overdispersion assumption in order to fit the Poisson regression model. Due to the overdispersion problem in the Poisson regression model, standard errors might be underestimated, which may lead to a highly misleading inference. There are several tests in the literature to check the presence of overdispersion in the Poisson model. In this study, we apply a regression-based t test to identify the overdispersion. The simulation study and real data example clearly show that the overdispersion in the Poisson model is caused by the existence of outliers.\nInternational Journal of Statistical Sciences, Vol. 23(2), November, 2023, pp 31-37</jats:p>","journal":"International Journal of Statistical Sciences","year":2023,"id":630374,"datarank":0.20794415416798362,"base_score":1.3862943611198906,"endowment":1.3862943611198906,"self_citation_contribution":0.20794415416798362,"citation_network_contribution":0.0,"self_endowment_contribution":0.20794415416798362,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1633047,"name":"Abu Sayed Md Al  Mamun","orcid":null,"position":1,"is_corresponding":false},{"id":1633048,"name":"FM Arifur Rahman","orcid":null,"position":2,"is_corresponding":false},{"id":1633049,"name":"Hanaa Elgohari","orcid":null,"position":3,"is_corresponding":false},{"id":190794,"name":"Sohel Rana","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Outliers as a Source of Overdispersion in Poisson Regression Modelling: Evidence from Simulation and Real Data","abstract":"<jats:p>The Poisson regression model is a well-known technique for modelling count data. However, it is necessary to satisfy the overdispersion assumption in order to fit the Poisson regression model. Due to the overdispersion problem in the Poisson regression model, standard errors might be underestimated, which may lead to a highly misleading inference. There are several tests in the literature to check the presence of overdispersion in the Poisson model. In this study, we apply a regression-based t test to identify the overdispersion. The simulation study and real data example clearly show that the overdispersion in the Poisson model is caused by the existence of outliers.\nInternational Journal of Statistical Sciences, Vol. 23(2), November, 2023, pp 31-37</jats:p>","is_dataset_classified":null,"base_score":1.3862943611198906,"endowment":1.3862943611198906,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"19910364","pmcid":null,"openalex_id":"https://openalex.org/W4389204943","authors":[],"funders":[],"total_grants":0,"fwci":0.8534,"citation_percentile":0.76327869,"influential_citations":0,"citation_trend":[{"year":2024,"count":1},{"year":2025,"count":2}],"oa_status":"hybrid","license":"cc-by-nc-sa","oa_locations":[{"url":"https://www.banglajol.info/index.php/ijss/article/download/70105/46981","host_type":"journal"},{"url":"https://www.banglajol.info/index.php/ijss/article/download/70105/46981","host_type":"publisher"},{"url":"https://doi.org/10.3329/ijss.v23i2.70105","host_type":"journal"}],"fields_of_study":["Statistical Methods and Bayesian Inference","Transportation Planning and Optimization"],"mesh_terms":[],"keywords":["Overdispersion","Poisson regression","Quasi-likelihood","Outlier","Poisson distribution","Statistics","Regression analysis","Econometrics","Count data","Mathematics","Zero-inflated model","Regression","Inference","Computer science","Artificial intelligence","Medicine","Population"],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-05T21:07:10.317056Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}