Media Buying: Gross Rating Points

The following information applies to radio advertising for products and services that have long purchase cycles (Heating and Air Conditioning, Jewelry, Cars, etc.) It is not meant to be instructive for products with short purchase cycles (food, entertainment, etc.) or for special events.

Bad radio ads fail because they say nothing of consequence to the listener.

Good radio ads fail because they are scheduled to reach too many people with too little repetition. Radio scheduling decisions guided by a consideration of Gross Rating Points are virtually guaranteed to reach too many people with too little repetition (frequency.)

The average radio ad needs to be heard by the same listener at least 3 times within 7 nights sleep, week after week after week. Don’t skip weeks. Sleep erases advertising.

The minimum number of consecutive weeks your 1-week schedule will need to air is a function of the Product Purchase Cycle of the product or service in question. The longer the purchase cycle, the longer the weekly radio schedule will need to air before it begins delivering maximum ROI (return on investment.) Results begin very slowly for products and services with long purchase cycles. Think of the early weeks as the “ramping up” period. Or, if you’d prefer to see it from the advertiser’s perspective, these early weeks are the “chickening out” period. 

The correct radio schedule is a 1-week schedule that achieves at least a 3-frequency with as much Net Reach as the advertiser can afford to sustain.

Net Reach is the number of different persons who will hear your ad a specified number of times. If you were to generate a report for a 6-week or 14-week schedule, the net reach would be the collective or “cumulative” number of different people reached over the 6 or 14 weeks in question. But since we are deeply concerned with the ratio of repetition to sleep, we must reject any report other than the 7-day “typical week” report. This same “typical week” must run week after week after week. REMEMBER: the same person needs to hear the same ad 3 times within 7 night’s sleep. Our computer-generated Reach and Frequency Analysis needs to show us a weekly “Net Reach” number with a frequency (repetition) of 3.0 or higher.

(The only way to reduce an ad’s need for repetition is to craft a message of such credible urgency that a significant number of listeners will take action even though they are not yet in the market for the product in question. But this is MUCH easier to plan than to do. Advertisers often convince themselves they have created a “compelling offer” when they have in fact created the “average ad” we referred to in paragraph three.)

The math that underlies the calculation of Gross Rating Points virtually guarantees your radio ads will reach too many people with too little repetition (frequency.)

Bill Bernbach famously asked, “Would you rather reach 100 percent of the people and convince them 10 percent of the way, or reach 10 percent of the people and convince them 100 percent of the way?”

He was speaking, of course, about Reach and Frequency.

Reach: the number of different people who encounter your message.

Frequency: The number of times they encounter it.

Reach x Frequency = Gross Impressions

When the number of Gross Impressions achieved by an ad campaign is equal to the population of the trade area in question, you have achieved 100 Gross Rating Points.

In other words, 100 Gross Rating Points is the mathematical equivalent of reaching 100 percent of the population of a trade area, 1 time each. 

Or 50 percent of the population twice. 

Or 25 percent of the population 4 times. 

Or 10 percent of the population 10 times. 

Or 1 percent of the population 100 times.

Each of these is 100 Gross Rating Points.

Q: But would each of these schedules produce the same results?

A: Of course not.

I’ll end with an example I witnessed only last week.

I was asked to evaluate a 14-week radio schedule in one of America’s largest cities for which the advertiser had committed to pay 150,000 dollars. I was informed that a highly qualified professional media buyer had negotiated the schedule at a very low cost per Gross Rating Point (GRP.)

Prior to looking at the schedule, I predicted it would reach far too many people with too little repetition. “It’s almost unavoidable,” I said, “when you’re hungry for Gross Rating Points.”

“Don’t worry about your reach; worry about your weekly frequency,” I told them. Don’t let it fall below 3.0 per week. Don’t try to reach more people than you can afford to reach 3 times every week. Create an effective 1-week schedule and air it on the same station week after week after week. Don’t move it from station to station. Consistency is the frequency of the frequency, the repetition of the repetition. Let the Net Reach be whatever your budget can provide, but never settle for less than a 3.0 weekly frequency.”

The good news is that the $150,000 schedule - spread across 4 stations – was going to deliver a Net Reach equal to 72 percent of the total population of that city during the 14-weeks in question. And guess what? It delivered a 4.7 frequency!

Not a weekly 4.7 mind you, but a 4.7 frequency spread across the 14 weeks, collectively. In other words, the typical listener would hear the ad once every 20 days.

That schedule is virtually guaranteed to be ineffective.

The answer? Put all the money on one station and don’t settle for less than a 3.0 frequency each week. If the Net Reach drops from 72 percent of the population down to just 13 percent or less, that’s fine. The lifeblood of radio is frequency and consistency. Thirteen percent reach with a 3-frequency each week for 14 consecutive weeks means roughly 750,000 people in that city will have heard the message of that advertiser a few dozen times each. 

And believe it or not, the average commercial message requires that kind of repetition in today’s overcommunicated society.

Bill Bernbach was one of the great ones. 

More people should have listened to him.

Roy H. Williams

Google devastated the effectiveness of Yellow Pages advertising.

Television has been crippled by DVRs, Netflix and other streaming video sources. 

Newspapers in a digital age tell us what we’ve already known for 24 hours. 

Radio alone, of all the major media, has been able to retain most of what it once had. (Radio has lost only about 7 percent since the dawn of the digital age. CDs, iPods and satellite-delivered-radio each barked loudly at broadcast radio but their bite was very soft.) Pandora personalized online radio could possibly grow large enough to seriously challenge broadcast radio in the future and give advertisers a new way to reach the masses, but right now all we’re hearing is barking. This could change, but not overnight. 

I’m keeping an eye on it.

By Roy H. Williams, The Wizard of Ads at  

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