On the nature of over-dispersion in motor vehicle crash prediction models.

@article{Mitra2007OnTN,
  title={On the nature of over-dispersion in motor vehicle crash prediction models.},
  author={Sudeshna Mitra and Simon Washington},
  journal={Accident; analysis and prevention},
  year={2007},
  volume={39 3},
  pages={459-68}
}
Statistical modeling of traffic crashes has been of interest to researchers for decades. Over the most recent decade many crash models have accounted for extra-variation in crash counts--variation over and above that accounted for by the Poisson density. The extra--variation--or dispersion--is theorized to capture unaccounted for variation in crashes across sites. The majority of studies have assumed fixed dispersion parameters in over-dispersed crash models--tantamount to assuming that… CONTINUE READING