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Arbitron: PPM Data Is Different Than Internet Music Services’ Audience Estimates

Audience research firm cautions stations, ad agencies, networks from comparing its PPM audience estimates to those derived from Internet music service in-house server log files.

Arbitron has cautioned its clients not to compare what it feels are apples to oranges.

Without using company names, the audience research firm said in a memo that recent releases of audience estimates for Internet music services have raised questions about the comparability of Arbitron’s survey-based Portable People Meter radio audience estimates to estimates derived from server log files.

Pandora released ratings last week, we reported.

“Arbitron urges those reviewing audience estimates from Internet music services not to make direct comparisons to Arbitron audience estimates in any market,” say Arbitron President/CEO Bill Kerr and EVP/COO Sean Creamer in the memo, which was distributed to clients and trade press.

In response to client questions, Arbitron raises the issue of whether its PPM-derived radio audience estimates are equivalent to self-reported audience estimates derived from Internet music services’ in-house server log files. In a word, “no.”

Arbitron says there are differences in AQH and Cume metrics between “one-to-many” broadcast stations and “one-to-one” Internet music services. The company says it publishes a Description of Methodology suggesting some Internet measurers do not, and it raises the question of whether a person is completing the survey task and should be counted as “exposed” to the content.

For example, according to Arbitron, server measurement tells you if a session has begun but it may not tell you if anyone is really there throughout the session. Arbitron points out that a PPM uses a motion detector so it knows if the panelist is nearby. It also requires a minimum amount of motion per day or else the listening is not counted.

Unless the Internet music service employs some form of validation, it is not possible to know if the information provided is correct, Arbitron tells its clients. “For example, if a person uses more than one account, it could impact any measure of Internet music service reach or Cume, which is the number of different persons tuning-in, because a single person could be counted more than once,” the company states.