Crude and age-adjusted prevalence
The page of a county, a place or a state has a switch between two versions of each estimate. CDC publishes both. They answer different questions.
Crude prevalence
Crude prevalence is the estimated share of all adults of the area who report the condition or the behavior. It describes the area as it is. The age mix of the area is part of the figure.
Age-adjusted prevalence
Age-adjusted prevalence is the share that the area would have if its adults had the age mix of the 2000 US standard population. Some conditions, for example arthritis and high blood pressure, are more common at older ages. An area with many older adults has a higher crude share for them. Age adjustment takes away that difference. Then two areas can be compared on something other than the age of their residents.
CDC says:
Finally, age-adjusted estimates that adjust for potential differences in the age-distribution across geographic units can be used for county- and place-level comparisons.
Centers for Disease Control and Prevention, PLACES Frequently Asked Questions (page dated 11 Dec 2025, read on 2 Oct 2026)
Which one to read
- To describe an area, read the crude figure.
- To compare areas with different age mixes, read the age-adjusted figure.
- For a ZIP Code, only the crude figure exists.
We don't provide age-adjusted prevalence estimates at census tract and ZCTA levels because some of these areas do not have population in all age groups used in the adjustment process.
Centers for Disease Control and Prevention, PLACES Frequently Asked Questions (page dated 11 Dec 2025, read on 2 Oct 2026)
The site computes the state figures in both versions, as site aggregates of the county figures. The national row is the row of CDC, in both versions.
Last checked against the CDC pages: