No rush to measure Limbaugh’s ratings

How many people actually listen to Rush Limbaugh, the radio talk titan White House officials have spent the last week characterizing as “the head of the Republican Party”?

According to what Limbaugh delights in calling “the drive-by media,” the number varies wildly. Is it 30 million (Pat Buchanan on MSNBC), 20 million (Time magazine, ABC News), 19 million (Fox News), 14 million (CNN), or “14.2 million to about 25 million” (Washington Post)?

Answer: Maybe.

Limbaugh is widely acknowledged to be the most popular talk host on terrestrial radio, as evidenced by the $400 million, eight-year contract he signed with his syndicator last July. (Howard Stern signed a deal with Sirius Satellite Radio in October 2004 for a reported $500 million over five years.) But estimates of Limbaugh’s nationwide (and overseas) audience are exercises in guesswork, slippery methodology and suspect data. Limbaugh himself has muddied the water with the claim that he reaches 20 million people a week, although there’s no independent support for it.

Arbitron, the radio industry’s dominant audience-measurement company, can say with some precision how large Limbaugh’s audience is in a particular city and at a particular time, but it has never publicly released a national estimate for his show.

The difficulty comes from the vast patchwork that is Limbaugh’s radio empire. His three-hour daily program is carried on more than 600 domestic stations, but these stations don’t all carry the show at the same time or even for the same duration. Like KFI-AM (640) in L.A., most stations air all three hours of Limbaugh’s broadcast each weekday, but some carry only two hours. Arbitron has never attempted to aggregate all of this audience data for these many stations and times.

“There is no economic motivation for any objective third party to do that kind of analysis,” says Thom Mocarsky, an Arbitron spokesman.

And there are no ratings at all for a constituency of Limbaugh listeners: U.S. military personnel stationed overseas. Limbaugh’s program is carried to these listeners on about 400 stations of varying audience sizes via the Armed Forces Radio Network, which Arbitron doesn’t monitor.

Premiere Radio Networks, Limbaugh’s national syndicator, estimated last year that 3.59 million people were in Limbaugh’s audience during an average quarter-hour of his program, based on a review of Arbitron’s piecemeal data about hundreds of stations.

Because people typically tune in and tune out of stations, however, this number doesn’t reflect how many individuals cumulatively listened at some point during the week. What’s more, Premiere’s figure is based on data from the first three months of 2008, a virtual lifetime ago in the fast-moving radio business.

Figuring the size of Limbaugh’s flock “is an art, not a science,” says Michael Harrison, editor of Talkers magazine, a trade journal about the talk-radio field. “It’s hard to come up with an exact answer. It really reveals the embarrassing state of radio ratings.”

Harrison’s own calculation -- that Limbaugh typically attracts about 14.25 million listeners weekly -- is based on Arbitron figures from about 30 cities and spot checks of a similar number of stations. Harrison stands by his guess. “Once you get below the big markets, [the audience] doesn’t add up to critical mass,” he said.

Harrison said his estimate of a big spike in Limbaugh’s audience last week -- some 25 million -- was also based on his discussions with station program directors around the country. “It’s what we’re hearing, based on the e-mails, the calls, all the buzz this controversy is generating,” Harrison said. “We put a little bit of our interpretation on it, added it all up, and that puts you in the ballpark.”

No matter the exact figure, Harrison says Limbaugh’s weekly audience eclipses all other nationally syndicated personalities, including Sean Hannity (13.25 million), Michael Savage (8.25 million) and Laura Ingraham (5.5 million), according to the magazine’s “rough projections.”