By popular request, we're going to attempt to explain some of the mystery surrounding the Arbitron ratings. It is, according to all concerned, an imperfect system. A perfect system would have some sort of monitoring device on every single radio in every single house that would record what station is tuned in when. This, of course, would be impractical, if not impossible, and we won't even get into that Orwellian stuff it brings to mind. Instead, Arbitron carefully selects households -- at random, but within specific geographic and demographic parameters -- each of which completes a diary of what is listened to in a one-week period during a ratings quarter (the ratings come out four times a year).

Arbitron then compiles a myriad of statistics from all these diaries (about 5,000 are distributed each quarter). If a station wants to know how many males aged 18 to 35 tune in from 7 to 9 a.m., Arbitron has that number. The same goes for virtually any other age group and virtually any other time of day. In addition (and there are more in additions here than we'd care to shake a stick at), a station manager can determine the time an average listener spends listening to the station, the number of times a listener is exposed to an ad and the number of different people who tune in at any given time. (This is a different figure from the number of listeners, which can include the same person tuning in and out over a period of several hours.)

What this all translates into is a mess of statistics that radio stations can pick and choose from to sell advertising. Mr. Sales Manager says to Ms. Advertiser, "While it would appear that we're down in the ratings, if you look here you can see that among white females, aged 45 to 50, we're the Number 1 station from 10 to 11 Sunday nights. And these are precisely the people you're trying to sell Widgets to." You may not think Ms. Advertiser would be swayed, but at the same time, Mr. Sales Manager is exactly right. What's more, because the overall ratings are down, Ms. Advertiser can bargain and get Mr. Sales Manager to cut his rates a little. So everyone is happy. Within limits.

Many station managers think the ratings are skewed in favor of stations tuned in by older listeners, because they're more likely to take the time to complete their diaries accurately. (Arbitron officials were all at a national sales meeting last week, so we'll get their side of the story next week.) But while no one is particularly enamored of the system -- except the No. 1 station -- everyone recognizes its importance in determining ad rates and in gauging the long-term progress of a station. Fluctuations such as WDJY's and WAVA's plunges in the fall book can be dismissed as one-time blips. But two-, three- and four-time blips are a sure indicator that a station, not the ratings, needs to be fixed.

WRC's Growth

Speaking of ratings blips, we inadvertently blipped WRC (980) right out of the ratings summary last week. The station ranked 15th with a 2.3, up from a summer share of 2.1. The increase was encouraging, said one WRC staffer, as it was the first ratings period to reflect the all-talk format begun last summer, and showed that the station is beginning some growth.

Finally, some nonratings news: Milt Fullerton has joined WRC as an afternoon news anchor. Fullerton has been a foreign correspondent for both NBC and ABC radio, and served as chief correspondent and morning anchor with the Pennsylvania Network and as an anchor with NBC Radio.

WAVA's Soviet Hookup

Remember when WAVA-FM's (105.1) "Morning Zoo" played selections from the Soviet Top 10 during Gorbachev's visit? Back then, station General Manager Alan Goodman said he hoped it would lead to further exchanges with the Soviet Union, and it has.

On Sunday at 10 a.m., WAVA will present "Kids to Kids," a live, 90-minute (more or less) show linking American and Soviet teens (with simultaneous translation of the two) via satellite and Radio Moscow Channel 1. Late last week WAVA was still looking for high school students from the Washington area to participate in the exchange, and students have been asked to submit nonpolitical questions they would like to ask their Soviet counterparts. Five students will be chosen to take part.

The program, to be hosted by WAVA News Director David Haines, will be available to 70 million homes in the Soviet Union, and arrangements are being made here to carry the show on stations throughout the United States. In addition to the in-studio panel, questions will be taken through a toll-free 800 number set up at WAVA.