Models for Response Data Showing Extra‐poisson Variation

When count data show extra‐Poisson variation, standard log‐linear techniques to analyse the data may fail. In ihis paper a generalization of the log‐linear modelling technique is proposed for the negative binomial model, as an extension of the Poisson model. An illustration is given by the analysis of a twoway classification of soldering failure data; extensions to more general classifications are possible.