Methodology of a cerebral palsy register. The Western Australian experience.

Population-based disease registers serve a variety of purposes and have proven their value in stimulating and facilitating epidemiological research and health planning. The methods used to establish and maintain the Western Australian Cerebral Palsy Register are described. Efforts to reduce diagnostic variation by regular interobserver study meetings with clinicians have been highly productive in addition to promoting awareness of the requirements of the register. The existence of perinatal data sets as denominators are essential to monitor trends, which in turn generate hypotheses that can be readily investigated with the case population and basic variables already identified. The costs of setting up and running an ongoing register are thus offset by its output and potential uses. These, as well as its limitations, are discussed.