A classification of disease mapping methods.

This paper considers the underlying principles of depicting disease incidence on geographical maps and uses them to attempt a comparative classification of methods. After a discussion of the possibilities for incorporating time, we consider projection methods, some of which have been used to portray information in a manner supposed to be independent of population density. We then distinguish between non-parametric and model-based methods, including models for areal data using Bayesian ideas. Data in point form are also discussed and it is argued that the relative risk function provides a fundamental model useful for assessing different methods as a whole, some of which are known to be flawed and many of which are untested as regards their statistical properties.