Lim, Hwa Kyung; Song, Juwon; Jung, Byoung Cheol - In: Computational Statistics & Data Analysis 61 (2013) C, pp. 67-82
In a Poisson regression model in which observations are either clustered or represented by repeated measurements of counts, the number of observed zero counts is sometimes greater than the expected frequency by the Poisson distribution and overdispersion may remain even after modeling excess...