The GBD 2000 aims to produce the best possible evidence-based description of health, the causes of lost health, and likely future trends in health. To the extent possible, the GBD 2000 aims to utilize and synthesize within a consistent and comprehensive framework, all relevant epidemiological evidence on population demography and health for the various regions of the world. Where evidence is uncertain or incomplete, the GBD 2000 attempts to make the best possible inferences based on the knowledge base that is available, and to assess the uncertainty in the resulting estimates. This paper summarizes the analysis categories, methods and data sources for the GBD 2000.