RE: Recent ratings thoughts....

[Roger Kirk <rkirk@videoserver.com>]

Bump Martin wrote:
>Now about Arbitron....
>I've noticed this footnote for years at the bottom of rating books for a
>long time.  "Stations audience estimates adjusted for actual broadcast
>schedule."  Usually (if not always) associated with a daytimer.
>What does this mean?  Does this mean the number is "massaged" as
>if they were on the air the entire daypart?
>i.e....If WILD gets a 1.0 for the 7-12MD daypart....does that discount
>the hours they are off and only count the hours they have a product on
>the air?  Or do they count the time that they have ZERO listeners after
>sign-off?

It was explained to me thusly:

Say there are two stations, WAAA and WBBB.  WBBB is a daytimer.

WAAA is on for the full daypart 6-10a.  WBBB signs on at seven (this
mythical month) so they are only on for part of the daypart.

WAAA gets a 4 rating, based on 1000 AQH persons in each of sixteen
quarter hours between 6am and 10am.

WBBB has identical audience when it is on the air (7-10).  1000 AQH
persons.  But if you do the math without "correcting" for the fact they
are a daytime, they would only get a 3 rating., because they'd have four
quarter-hours with no listeners.

Fact is, when somebody signs on and if they have listeners, (if PUR, the
number of persons using radio doesn't change) everyone else would dip
down a bit, in terms of rating, so Arbitron does a math correction to
allow for the fact that there are now N+1 stations on the air.  Now, if
everyone who listens to WBBB simply has a clock radio which clicks on at
7, then PUR will go up by exactly the same amount as their AQH persons
at that time.  Thus, WBBB gets their listeners and nobody else is hurt.

It's never that simple, of course.

So Arbitron has a correction algorithm for all of this.  It's not as
simple as plugging into the figure zero listeners for the daypart.  It
accounts for AQH persons, shares (related to the PUR for the hour as
opposed to the whole daypart), cumes and so on.  I have no idea what the
math is.  Perhaps Arbitron could make it clearer, but I bet not.

Roger Kirk

------------------------------