Poisson regression models are widely used in analyzing count data. Dean & Lawless (1989) and Dean(1992) developed the tests for overdispersion in Poisson models with non-repeated measurement.

• Poisson回归模型广泛应用于分析计数型数据 ；Dean &Lawless(1989)和Dean(1992 )讨论了非重复测量得到的计数型数据的偏大离差存在性的检验问题 .