Piling on GRP or CPM does not always increase a marketing message’s reach

In 1972 my best friend and I decided to go to Pamplona to run the bulls. From July 7-14, we danced in the streets, ran in front of six bulls every morning and drank cheap wine to excess. How much excess? Well, we were drinking non-stop four days in a row. It was so bad that, after we came back to Madrid, we didn’t touch the stuff for almost an entire year. That’s Mike, in the picture, still drinking away from a bota.

Media is pretty much like that. We sometimes pile on those cheap gross rating points (GRPs) or cheap cost per impressions (CPMs) not realizing–or realizing too late most of the time—that the whole thing is not working and we’ve wasted a huge amount of money.

Reach, Frequency and Quintile Distribution

Now, television–and, really, almost any massive-enough media—can build reach quickly. But what happens when you max out your reach? You get frequency. And the formula is very linear: GRPs/Reach = Frequency.

So, what happens with the TV audience? Well, frequent viewers view a lot and light viewers don’t. Quintile distribution is a quick and easy way to look at a TV buy and see where the money is going. In most countries (and I’ve done this in the U.S., all of Latin America and five European countries) the top 20 percent of all viewers get about 45 percent of the GRPs.