How was incidence extrapolated from 22 states to the entire United States and Washington DC?
• Incidence in 22 states was estimated in almost 70 strata (or subgroups) based on sex, race/ethnicity, age, and transmission category. Using the ratio of the number of new infections to the number of AIDS cases within these strata based on the 22 states, incidence was extrapolated using the number of AIDS cases within these strata for the remaining states and the District of Columbia (all grouped together). This method assumes that the strata-specific ratio of HIV infection to AIDS incidence in the 22 states (all grouped together) is similar to the ratio in other states and DC (all grouped together), an assumption generally supported by historical trends in HIV and AIDS diagnoses in the United States • How can states calculate their own area-specific incidence estimates? • For states that are not conducting HIV incidence surveillance, local data on HIV diagnoses are best to describe the status of the local epidemic. These states do not have the data that are needed to compute their ow
