PPM vs Minorities

[Garrett Wollman]

<<On Wed, 03 Sep 2008 16:07:59 -0400, Roger Kirk <rogerkirk@ttlc.net> said:

> It would appear that the results are significantly different.  Which I 
> would expect, since the PPM is supposed to be a better measurement based 
> on actual listening vs what a diary-keeper can remember.

Let's be careful here.

The PPM doesn't measure listening, it measures exposure.
The diary doesn't measure listening, it measures recall.

Listening is what advertisers and broadcasters actually care about,
but it's nigh-impossible to measure under non-laboratory conditions.
So they measure something else which they have reason to believe is
positively correlated with listening.  The early results are fairly
clear that people have more exposure to radio than they can recall,
but it's not obvious to me how much of that additional exposure is
background noise versus actual listening that went unrecorded.

(There is a long history of problems with the diary method where
survey participants would recall stations with strong imaging even
when their actual listening was minimal.)

-GAWollman