Monday, July 18, 2011

Track This Number, Especially If You're In A PPM Market

The average household size in diary sample markets across both the USA and Canada has trended almost exactly the same as the census average, roughly 2.6 persons per home for a very long time.

Over the five decades I have been studying diary samples, there have been individual weeks during BBM or ARB survey periods when the number of persons per household for the total sample and individual radio stations have wobbled wildly away from that average, but when tracking multiple weekly samples for eight to twelve weeks it almost always trends back up or down to the norm.

Not so in PPM markets, where one very large household who loves (or hates!) your radio station can stay in the sample for 24 months or longer. That small number of high occupant households has the potential to help or harm your audience estimates for several years, giving new importance to fully understanding reliability in statistical terms.

If your station hits new, never before attained in diaries, high numbers in PPM:

1. Celebrate. Enjoy. Savor it. You have a station that some people use a lot and that's great.
2. Track the average number of people per ethnic and non-ethnic household in the total sample and also in your station's panelists week by week.
3. Troll for more homes just like them in your marketing efforts.
4. Educate your owner and manager. Hope that they understand that Newton's laws also apply to stats as well as physical objects. What goes up goes down as well.

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