The first batch of radio ratings obtained through Arbitron's new electronic system presents a very different picture of Philadelphians' listening habits.

Many stations are boasting larger audiences - but the audiences are more restive, flipping the dial more than Arbitron previously estimated.

In a national movement starting with Philadelphia, Arbitron recently began using pager-size Portable People Meters to measure listening, ending a four-decade practice of paper diaries. Arbitron has long believed that diaries are fraught with potential for misreporting; PPMs, meanwhile, passively capture special tones embedded in radio signals.

Arbitron says PPMs also allow ratings to be released monthly, rather than quarterly, enabling stations and advertisers to act on information more quickly.

The initial report, covering March 8 through April 4, showed little change in rankings among rock, oldies and news formats.

However, the time spent listening sank dramatically; the weekly average among listeners ages 12 and older dropped from 20 hours last fall to 121/2. PPM indicated that Philadelphians listen not to two or three stations, as paper diaries said, but to five or six.

This dial-switching has sent audience sizes soaring. Under diaries, only all-news KYW-AM (1060) claimed a weekly cumulative audience of greater than one million people. Now, according to PPM figures, nine stations had a "cume" of more than one million. Light rock WBEB-FM (101.1) had the largest cumulative audience - just over two million people - followed by classic hits WOGL-FM (98.1), KYW and classic rock WMGK-FM (102.9).

B101 also had the highest share of listeners in an average quarter-hour (see the accompanying chart).

PPM is "a complete paradigm shift in the way radio is measured," said Blaise Howard, B101's general manager. "The big upside is that radio has tremendous potential for reach."

Arbitron reported that while African Americans still report the highest time spent listening of all consumer segments, stations targeting urban audiences suffered under the new system.

Among all listeners ages 12 and over, urban adult contemporary station WDAS-FM (105.3) fell from second place in the fall 2006 ratings to seventh place in March. Among listeners ages 25 to 54, its target, WDAS dropped from first to sixth - its estimated adult audience per quarter-hour off 30 percent.

The PPM report was good news at rock WMMR (93.3), which was the top station among adults 18-34 and 25-54. WMMR's average-quarter-hour share rose 126 percent among the listeners 18-34.

WMMR claimed nearly one in six listeners in that age group - nearly twice the share of its nearest competitor, urban contemporary WUSL-FM (98.9). That station, known as Power 99 and the historic No. 1 station among 18-34s, saw a 19 percent share loss. Last fall, Power 99 was fourth among all listeners ages 12 and over; in March, it was 11th among ages 12 and older and 10th among listeners ages 6 and older. (Arbitron has begun using "6-plus" as the new standard, but "12-plus" numbers are still available for comparison.)

The National Association of Black Owned Broadcasters issued a statement questioning the PPM methodology, and the makeup and administration of the sample panel. The NABOB is holding meetings with Arbitron.

In an interview, Arbitron spokesman Thom Mocarsky said the ratings service is trying to refine the sampling and expand the pool of surveyors. He also said PPM numbers are more reliable because surveyors are monitored for the entire month, not just a week as they were under paper diaries.

Also under PPM, noncommercial stations are listed. WHYY-FM (90.9) was the highest-ranked noncomm; it was 10th among 12-plus and 11th among 6-plus audiences. WXPN-FM (88.5) was 20th among 6-plus.

Monthly Radio Rankings

The Arbitron ratings service has switched from paper diaries to electronic devices to measure radio listening. The March results are the first under the new system. The last full ratings period under paper diaries covered fall 2006.

March   Station    Format   Fall

2007         2006

1   WBEB-FM (101.1)   Light rock   1

2   KYW-AM (1060)   News   3

3   WMMR-FM (93.3)   Rock   6

4   WOGL-FM (98.1)   Classic hits   4

5   WMGK-FM (102.9)   Classic rock   8

6   WXTU-FM (92.5)   Country   7

7   WDAS-FM (105.3)   Adult urban comtemp.   2

8   WBEN-FM (95.7)   Hits   12

9   WPHT-AM (1210)    Talk   9

10   WHYY-FM (90.9)   News/Info   N/I

SOURCE: Arbitron, ranking of average listeners per quarter-hour, ages 12 and older.

N/I: noncommercial station not included in previous rankingsEndText

Contact staff writer Michael Klein at mklein@phillynews.com or 215-854-5514.