A few years ago, when I was buying magazine ad space for my table planner software, I was told by an ad salesman that customers need to see an advertisement seven times before it is effective. How very convenient for his commission. I have heard variants of this “advertising rule of 7” quite a few times since, but I have never been able to find out where it originally comes from. I have now taken to asking people that quote it what evidence they have to back it up. So far no-one has been able to point me at a paper, study or any other form of credible evidence.

I have just searched google for see “ad seven times” and I found lots of mentions of the “advertising rule of 7”. Here are some of them that appeared high in the search results:

But again, no links, references or citations to back it up, even from the people that said it was based on “statistics”, “surveys” or “research”. What statistics/surveys/research? Is it based on some form of scientific study that can be reproduced, is it a rule of thumb that has been given more credit than it deserves or is it total bullshit made up by a crafty ad salesman? I suspect the latter, but I would love to know. If you know the origin of this “rule of 7”, please post a comment below.

** Update 09-Jun-10 **

I have had some useful feedback from this post, particular in the private ASP forums[1] (always a great resource). David Trump posted a link to this paper:

THE REPETITION/VARIATION HYPOTHESES CONCEPTUAL AND METHOLOGICAL ISSUES [Schumann & Clemons]

I used references and keywords in this paper to find 3 other relevant papers:

Beyond Effective Frequency: Evaluating Media Schedules Using Frequency Value Planning [Cannon & Leckenby]

The shape of the advertising response function [Simon & Arndt]

The Shape of Advertising Response Functions Revisited: A Model of Dynamic Probabilistic Thresholds [Vakratsas, Feinberg, Bass & Kalyanaram]

These papers talk about an ‘advertising response function’. This is a curve plotting the number of exposures to an ad against the customer likelihood of being influenced. Some theorise that there is a threshold below which ads don’t have an effect, a saturation point above which exposures may have a negative effect and a sweet-spot in between. This ‘S’ shaped response function could provide some support for ‘you have to see an ad 7 times’, except support for the presence of a threshold effect seems to be weak to non-existent. Only one of the papers [Vakratsas, Feinberg, Bass & Kalyanaram] cited any evidence and that seemed less than convincing from my quick reading.

For effective frequency to be valid, advertising must be subject to a threshold effect, reflected in an S-shaped advertising response curve (Stankey 1989). But research suggests that, in actual advertising situations, response curves tend to be concave, characterized by Continually diminishing returns (Simon and Arndt 1980; Schultz and Block 1986; Zielske 1986). [Cannon and Leckenby]

In brief, then we are satisfied that the field experiments as a group show no solid evidence for increasing returns over operating ranges. … Taken together, the studies using physical and monetary variables add up to the conclusion that there are not increasing returns to advertising—that is, no S-shaped response function-over the normal operating range. [Simon & Arndt]

Futhermore, some of the papers mention a theory that a customer might have to see an ad 3 times, but none of them mention 7 times.

Krugman (1972; 1977) captured the imagination of the industry with his three-exposure theory, which described an intuitively appealing sequence of consumer responses to television advertising that appeared to be consistent with a communication threshold. He suggested that the first exposure causes consumers to ask, “What is it?” The second causes them to ask, “What of it?” The third exposure is both a reminder and the beginning of disengagement. … The magic number “three” came to be a commonly accepted industry standard (Lancaster, Kreshel and Harris 1986). [Cannon and Leckenby]

Al Harberg pointed out that those claiming a “7 times rule” might be confusing the ability to recall information (where 7 has been shown experimentally to be the “magic number” for short term memory) with the number of ad exposures taken to influence someone. Two completely different things.

So please shout “bullshit” very loudly next time you hear the “advertising rule of 7″ mentioned. Especially if it is by someone trying to sell you ad space.

[1]Private correspondence in the ASP forum referenced with permission.

** Update 13-Mar-19 **

Paul Moore writes:

“I read your blog post from a few years back, and thought you might find this of interest. It’s a article passed around several newspapers at least as far back as 1859. It showed up even in 1910. Here’s the earliest iteration I was able to find on Google – the text is identical in several other American newspapers of the time. I have no idea where it originated, but the theory has been around for a while. I guess in modern times the number of impressions went from six to seven!”