Odds of Hitting a PPM Holder

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Odds of Hitting a PPM Holder

Post by rogerwimmer » Wed Jun 22, 2011 10:04 am

Doctor: We are doing a modest marketing campaign that is estimated to reach roughly 100,000 people in my metro. (Our market size is close to #20, if that matters.) Of the 100,000 people we will supposedly reach, is there a way to know how many in that group might possess a PPM? Thanks for your excellent insight. - Anonymous

Anon: While your question sounds simple, it isn't because you have two different random events that come into play. I'll try to explain . . .

First, I assume the 100,000 people you are supposedly going to reach are from a specific target demo such as Adults 25-49. However, I doubt that the 100,000 "reach" group is the total number of 25-49 year-olds in your market. There may be 200,000 or more in the group. So, the people exposed to your message are going to be randomly "selected" from that group and there is no way to predict who and who will not be exposed to the message.

But you might be able to take an educated guess about who will be exposed to your campaign if the campaign has a very specific plan. For example, if you're using a TV campaign and you know the percentage of your listeners who watch a specific TV program and place your ads in that program, you could use the viewership percentage as a rough estimate of how many will be exposed to your campaign.

Second, although Arbitron's PPM (Portable People Meter) sample is a volunteer sample (respondents must voluntarily agree to participate, they can't be forced) the sample is close to a simple random sample. What that means is there is no way for anyone to predict which people in any market will participate in a survey. The odds of one person participating are no better or worse than anyone else in the population.

Third, the worst of all is that the first two items are not mutually dependent on each other in any way. That is, one event does not need the other to occur - one event can occur without the other. That's not good in reference to calculating your odds.

So . . . the situation you describe has three problems: (1) Identifying who will be exposed to your campaign; (2) Identifying who will participate in the Arbitron survey; and (3) No dependency of one event on the other. Those three characteristics make it virtually impossible for me to develop an "odds" for you. Oh, I'm sure there is a Las Vegas odds-maker who could produce the odds for you, but that would be a pure guess because the three problems cannot be overcome.

Now, you might say, "Hey, come on, just give me a guess for the heck of it." OK . . . here is a way you can guess, but I warn you ahead of time that the number is going to be small . . .

Look at the number of PPM respondents in your radio station's demographic (just use Adults for the age cell). Take that number and divide it by the total number of people in your market who are in that demographic and then divide that number by one half. That's my guess at the "odds" of someone in your target demo seeing your campaign and participating in Arbitron's PPM survey. And that, my friend, should be enough evidence to support the idea of constantly promoting your radio station, not just a few weeks before or during a survey.

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Roger Wimmer is owner of Wimmer Research and senior author of Mass Media Research: An Introduction, 10th Edition.

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