What is an “age-adjusted” incidence rate?
An age-adjusted rate is different from a crude rate in that the incidence rate is modified to take into account how the age distribution of the population of interest varies from a conventionally-used “standard population”. It is important that the same standard population be used so that age-adjusted rates can be compared to each other. The U.S. 1970 population has been used as a standard for many years, and the U.S. 2000 population will soon be used as the standard. Age-adjustment enables us to compare cancer rates among different countries, states, or counties.
