hamNcheese said:
In 20+ years that I have been aware of Arbitron diaries I know I know 1 person who has filled one out. Then again all my family & friends have cellphones, so they would never be considered at all. For years Arbitron has been flawed, based on recall and 'honesty' not actuall listening. I think that may have had an effect on ratings, stations, companies, jobs, stocks, ect...
The Arbitron sample is "small" compared to the general population... only 1 in about 1000 participate each survey, meaning it would take about 80 years to get asked to participate (including refusals and non-returns) and with the PPM, the sample is one third of the diary 3-month sample. That works, statistically.
What happened in the diary is that people round. It's not malicious, it's not "voting" or anything like that. Folks who really listened for about 50 minutes between 6 and 9 AM, wrote down 6 AM to 9 AM, because they did not deduct the 10 minutes of the alarm on snooze, the time in the bathroom, the time in the closet, the time getting from the house to the car, etc., etc.
So, of course, things change. We believe, or want to believe, that the PPM will eventually be better than the diary. Until it has MRC accreditation, it is not.