The new Event Retention Index metric uses PPM data to “estimate” the proportion of a radio station’s audience that stays tuned in for complete quarter hour sections of a sports match, compared to the average audience of top 20 stations in the same market.

For example, Arbitron said that a Event Retention Index score of 120 would mean that the station in question’s listeners are 20% more likely to listen to quarter hour segments of sports broadcasting than other stations in the same market.

Arbitron Sports manager Chris Meinhardt said: “The Event Retention Index can provide tangible evidence that people who listen to sports broadcasts ‘stick around’ during games and are more likely to be exposed to advertising during the broadcast.”