Unduplicated Total Reach is the number of unique people who live within the combined coverage areas of the stations you selected. If a person lives in an area covered by more than one station, they are counted only once.
Census Tract Reporting breaks down where those people are. "Station A only" means people who can receive Station A but not the others. "Overlap" means people who can receive both (or all three) stations. These are not listeners — they are the population within signal range.
What is a census tract? A census tract is a small, relatively permanent geographic area defined by the U.S. Census Bureau for the purpose of collecting and reporting demographic data. Each tract contains between 1,200 and 8,000 people, with an average of about 4,000. They are the most granular geographic unit for which the Census Bureau publishes reliable population data. Cardigan tests whether each tract's geographic center falls inside a station's signal boundary.
Why this matters for buying: If two stations have nearly identical coverage areas (high overlap), buying both gives you frequency and format diversity but not additional geographic reach. If two stations have low overlap, buying both expands your reach to new communities. Both strategies are valid — this report helps you understand which one you're buying.
Coverage population per station is the total number of people living within that station's FCC-defined signal boundary, calculated from census tract data. This is not a listenership number — it is the opportunity baseline.
When a zone shows 0 tracts: This means every census tract covered by that station is also covered by at least one of the other stations in the comparison. It does not mean the station has no coverage — it means its coverage area is completely contained within the combined coverage of the other stations.
Data sources: FCC signal contours (60 or 54 dBu), U.S. Census Bureau American Community Survey 5-Year Estimates at the census tract level.