More Weeks, Less Weight: The Shelf-Space Model of Advertising

Erwin Ephron

Henny Youngman said it. 'I've got enough money to last me the rest of my life, provided I die at three o'clock.' That joke is the advertiser's nightmare. There's never enough money for a full year of advertising at effective weight-levels, so we make do. We use more 15s, buy cheaper TV, and run fewer and fewer weeks, driven by our belief in 'effective frequency,' the idea that it's the concentration of advertising that makes consumers buy.

Yet despite billions of advertising dollars and years of brand experience, the industry has failed to prove the value of effective frequency. Now there is strong evidence we have been riding the wrong horse. Professor John Philip Jones at the Newhouse School at Syracuse University (1993) and Walter Reichel (1993) of A-to-S Link, both using Nielsen single-source panel data, have found one exposure to a brand message has a greater effect on brand share than additional exposures. More disturbing, a recent ARF paper by Colin McDonald, whose research in the late 1960s was basic to the development of effective frequency theory, disputes the conclusion that his work ever supported the need for multiple exposures (1994). Perhaps effective frequency was never right. Perhaps it was right for the 1960s and '70s and is just wrong for today. Either way, we need to rethink how best to spend the client's money. I suggest the better way is to plan media for weekly reach.