The broadcaster’s vice president of audio research and special projects, Tom Evans, told Research: “This is not an ‘either/or’ [situation] but an ‘and'.” When asked how long the firm intended to use ratings from both firms, he said: “Who knows?”

Nielsen entered the radio ratings market last year when it won the contract to become Cumulus Media’s “ratings partner” in the 51 markets. Clear Channel Radio signed up to use data for 17 of those markets at the time, and recently added the Newburgh/Middletown market to the list of regions it uses Nielsen data for.

The deal with Cumulus bought Nielsen into direct competition with Arbitron, who vowed not to “concede any turf” to its new rival.

As well as ESPN, two media agencies – Schnucks Creative Services and Meridian Chiles – have signed up to use Nielsen’s radio ratings in the 51 markets.