Summary

Using Generalized Linear Models, you have fit three different models for count data. The negative binomial regression was shown not to offer any improvement over the Poisson regression. The overdispersed Poisson regression seems to offer a reasonable alternative to the standard Poisson model, but there is not a formal test for choosing between them.

Explanations of the mathematical foundations of the modeling methods used in IBM® SPSS® Modeler are listed in the IBM SPSS Modeler Algorithms Guide.