Categorical Data Analysis Using SAS, Third Edition, 3rd Edition

Chapter 12

Poisson Regression and Related Loglinear Models

Contents

12.1   Introduction

12.2   Methodology for Poisson Regression

12.3   Simple Poisson Counts Example

12.4   Poisson Regression for Incidence Densities

12.5   Overdispersion in Lower Respiratory Infection Example

12.6   Exact Poisson Regression

12.7   Loglinear Models

12.8   Analyzing Three-Way Cross-Classification Data with a Loglinear Model

12.8.1 Analyzing Loglinear Models with the CATMOD Procedure

12.9   Correspondence between Logistic Models and Loglinear Models

12.1 Introduction

Categorical data often appear as discrete counts that are considered to be distributed as Poisson. Examples include colony counts for bacteria or viruses, accidents, equipment failures, insurance ...