• by Erik Sass  @eriksass1, November 15, 2007

The radio industry gave voice to its dissatisfaction with Arbitron's Portable People Meter ratings in a blunt letter sent last night and signed by some of the country's biggest broadcasters. With signatories including Clear Channel Radio, Cumulus Media, Cox Radio and Radio One Inc., the letter demands immediate action by Arbitron to remedy the PPM rating system's shortcomings.

Specifically, the broadcasters demand that Arbitron meet its in-tab sample targets for all age segments in the 18-54 range and all ethnicities, including African-Americans and Hispanics.

The broadcasters complained in the letter that "to date, PPM has not provided accurate or reliable data for all demographic groups" in Houston and Philadelphia, the two markets where PPM ratings have "gone live" as radio currency. "The most immediate issue is sample size--especially with regard to 18- to-34-year-olds and ethnic groups." The issue is pressing because radio broadcasters sell ads targeting specific age groups and ethnic groups, among other demographic segments.

In fact, on Wednesday, MindShare said it will begin requiring audience-size guarantees, based on Arbitron PPM data, when it buys ad inventory in Houston. Those broadcasters that fail to achieve 90% of the target audience size, per PPM, will be required to make up the difference with extra ad inventory.

The broadcasters said the solution is simple: "The number of people participating in the PPM survey must be increased." While Arbitron has tried in recent months to meet sample size targets by recruiting more active participants to carry the PPM device, rather than leaving it docked in its charger, broadcasters say they have failed to do so.

More alarming to the broadcasters is Arbitron's proposal to lower the number of participants required for a sample size to be considered statistically valid. The broadcasters protest that "this proposal could result in some stations doing business based on the activity of as few as a single--one--listener." The letter notes that "your own researchers have concluded that such a sample size 'has a greater range of error than the size of the estimate.'"

To remedy the situation, the broadcasters suggest cutting the 6-11 sample, which has limited utility in ad sales, and transferring the meters to new recruits in the higher age groups, including Hispanics and African-Americans.

Broadcasters that target minority audiences have been especially critical of PPM results, saying Arbitron's failure to meet its sample-size targets among African-Americans and Hispanics are leading to precipitous drops in their ratings. The minority broadcasters were galvanized by the release of October PPM results for New York City, where PPM data is set to replace Arbitron's older diary system in January.

In these October "pre-currency" ratings, urban and Hispanic formats plunged in an alarming fashion. Among the stations taking the biggest hits: WRKS/98.7 FM, WBLS/107.5 FM, WQHT/97.1 FM, WCAA/105.9 FM, WADO/1280 AM, and WPAT/93.1 FM.