We buy airtime with multiple vendors, especially for TV. Does anyone know of a methodology for adding up the reach and frequency for each vendor? I am assuming that it is safe to simply add Gross Impressions and Gross Ratings Points within a given market, but the reach and frequency need to be weighted somehow...!
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adding up stats across vendors
(2 posts)- Started 1 year ago by sarahbruce
- Latest reply from geraldbelton
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Posted 1 year ago #
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You are correct that Gross Impressions and Gross Rating Points can be added. Gross Impressions can even be added across media and markets -- If a campaign has 10,000 gross impressions in Raleigh and 5,000 in Charlotte, it still has 15,000 gross impressions. (Don't try this with rating points, though!)
Reach and Frequency is more complicated. There are two ways to do this, one much more effective and one much simpler. The simple method is not precise, because the relationships are non-linear.
By far the best way to do this is using specific software that can integrate schedules across multiple media. We have software that would allow us to enter a combined schedule on our station, other TV stations in the market, and cable, and calculate a combined reach and frequency with great accuracy based on Nielsen's audience measurements. We also have software that will, with slightly less accuracy, allow us to add in radio and newspaper schedules and calculate multi-media reach and frequency.
The simpler way uses a formula: (R1+R2)-(R1*R2/100)*0.96 where R1 is the reach of medium 1, and R2 is the reach of medium 2. The implicit assumption is that probabilistic proportions apply across media. In other words, if a schedule on FOX 50 reaches 60% of your target, it also fails to reach 40% of your target. If an additional schedule on WRAL reaches 60% of your target, then it reaches 60% of the people you already reached on FOX 50, plus 60% of the 40% that you didn't reach on FOX 50. But we're assuming that cross-viewership is random, which it is not. (It might be that while the schedule on WRAL reaches 60% overall, a larger proportion of them also watch FOX 50.) The 0.96 is simply a "fudge factor" to allow for this unknown duplication.
Better than using this formula would be to ask one of your media partners to calculate the multi-media reach and frequency. I believe all of the TV stations in the market have a Research Director who should know how to do this. (I'll be happy to do it for any non-profit or government entity, even for media buys that don't include my station.)
Posted 1 year ago #
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