On the Statistic Tab in a Limited-Duration Prevalence session, if you choose age-adjusted percents as your statistic, you must also select an age variable. This age variable defines the age groups used for age-adjusting.
Age at Prevalence Date (Calculated) and user-defined versions of this variable are the only variables that can be used for age-adjusting. The groupings defined in the standard version of this variable are the same as the database's age recode variable. The age recode variable differs from one database to another based on the associated population and standard population data. For example, some have 18 age groups while others have 19. Variables used for age-adjusting cannot have overlapping or duplicate age groups. If you exclude an age group, it will be included as its own grouping in the age-adjusting calculations.
Variables concerning age at prevalence are called "calculated" because the age at prevalence is not coded in the database. This value is calculated based on the selected prevalence date and either date of birth (if available) or age and date at diagnosis.
Only valid age variables will be available in the Age Variable drop-down list on the Statistic tab.