The Total Survey Area (TSA) of an Arbitron radio market is designed to provide a comprehensive measure of listening to Metro-licensed stations. Audience estimates for the TSA are reported for the Spring and Fall surveys only.

The TSA is a geographic area composed of the Metro and any additional counties or split counties which meet certain criteria for inclusion. Counties are not split for the purpose of defining the TSA; however, any split counties which were created for the purpose of defining a Metro will be analyzed separately in the TSA qualification process. TSAs may cross state lines.

TSA definitions are based on historical radio listening patterns and are updated biennially from an analysis of diary data used for the most recent County Coverage study (excluding any additional sample ordered for Arbitron Custom Survey Area Reports [CSARs]). Updates are effective with the Fall survey of odd-number years (e.g., 1995, 1997) based on diaries returned for all four surveys of the previous calendar year (e.g., 1994, 1996, respectively).

A county or split county will be added to the TSA of a market if:

• At least 10 diaries were in-tab from the county; and
• The Metro-licensed stations cumulatively receive a minimum of 10 diary mentions; and
• The mentions to Metro-licensed stations account for at least 10 percent of the total mentions to all stations from that county (9.5 percent rounds to 10 percent).

The "10-10-10" rule outlined above is the basis for TSA qualification. However, strict application of the rule may not always produce a logical TSA or provide for the qualification of a county in which very few diaries are historically placed.

Therefore, a county which does not meet the "10-10-10" criteria outlined above may still be added to the TSA of a market if:

• At least 15 percent of its total mentions are to Metro-licensed stations, regardless of the number of in-tab diaries and/or number of mentions to Metro-licensed stations (14.5 percent rounds to 15 percent); or
• Approximately 75 percent or more of the county's border is contiguous with other counties in the same TSA.

Notwithstanding the above criteria, a county will not be added to the TSA of a market if it is not contiguous with the rest of that market's TSA.

TSAs for new markets are established in accordance with the above criteria, except that more recent diary data may be used, if available.

In order to stabilize market definitions over time, Arbitron has set the criteria for retaining counties in the TSA lower than the initial qualification criteria.

A county from which a minimum of 10 in-tab diaries were returned will be retained in the TSA of a market if:

• The Metro-licensed stations cumulatively receive a minimum of 8 diary mentions, and the mentions to Metro-licensed stations account for at least 8 percent of the total mentions to all stations from that county (7.5 percent rounds to 8 percent); or
• Metro-licensed stations cumulatively receive fewer than 8 diary mentions, but the mentions to Metro-licensed stations account for at least 10 percent of the total mentions to all stations from that county (9.5 percent rounds to 10 percent).

However, a county which does not meet the applicable criteria outlined above may still be retained in the TSA of a market if:

• At least 15 percent of its total mentions are to Metro-licensed stations, regardless of the number of in-tab diaries and/or number of mentions to Metro-licensed stations (14.5 percent rounds to 15 percent); or
• Approximately 75 percent or more of the county's border is contiguous with other counties in the same TSA.

Notwithstanding the above criteria, for purposes of maintaining survey area stability, a county from which fewer than 10 in-tab diaries were returned will generally not be deleted from a TSA.

The inclusion of a county in the TSA does not imply that all Metro-licensed stations have received diary mentions in the county. Also, because individual counties can, and often do, qualify for the TSAs of two or more markets, TSAs for adjacent markets frequently overlap. Thus, the TSA audience estimates for a particular station in one market may not be additive to TSA audience estimates for the same station in an adjacent market.