• by Erik Sass  @eriksass1, June 15, 2010

WPP/GroupM has signed a comprehensive deal for radio ratings from Arbitron, including data from its Portable People Meter, a passive electronic measurement system, in a number of large media markets, and paper diary ratings in small and mid-sized markets.

The new agreement, which renews an existing deal, represents a victory for Arbitron in its rivalry with Nielsen, which recently introduced a competing diary-based ratings service in mid-sized markets around the U.S.

The deal gives all of the agencies under the GroupM umbrella (including Maxus, MEC, MediaCom and Mindshare) access to Arbitron's PPM and diary ratings services, as well as Tapscan, Arbitron's software sales tool incorporating customized demos, geographies, dayparts and overall audience averages.

Among other things, the Tapscan service allows media buyers to calculate reach and frequencies based on demos and dayparts.

Over the last year, Nielsen has been promoting its diary-based radio ratings service for mid-sized markets. Nielsen claims its sticker-based diaries deliver more accurate data than Arbitron's diaries, which require panelists to write down what radio stations they listen to.

Moving to maintain its dominant position in the radio ratings business, Arbitron is wooing broadcasters with the promise of new ad effectiveness ratings, designed to address one of the key demands of broadcasters and advertisers alike.

Last year, Arbitron also announced the creation of a radio industry consortium to improve analytical methods for determining the actual impact of radio ads on product sales.

Also, this year seems to have brought the (tentative) resolution of a longstanding conflict between Arbitron and a number of minority radio broadcasters, which charged that Arbitron's PPM sampling methodology under-represented certain key minority demos, especially among African-American and Hispanic listeners.

The rapprochement follows Arbitron's commitment to enhance minority audience sampling, and the decision by groups -- including the Association of Hispanic Advertising Agencies -- to join the Media Rating Council, which oversees accreditation for media ratings.

Finally, Arbitron also settled its legal differences with one minority radio group -- the Spanish Broadcasting System -- following months of legal wrangling over SBS's refusal to encode its signals for PPM ratings, as agreed in its contract with Arbitron.