Postar hasn’t yet got the measure of outdoor ads

The impact of an outdoor ad isn’t arithmetically related to traffic and the size of the poster. Postar needs to acknowledge this, says Charles Hamlin

Most people don’t notice the majority of the men and women they pass every day on the street, but they can certainly remember the few who were particularly good-looking.

This is the perfect metaphor for UK outdoor advertising, with its masses of nondescript posters that are mostly lost on the viewing public. While many of the posters get seen, viewers remember only a few of the ads and brands on them.

Yet advertisers and agencies regularly buy outdoor on the basis of Poster Audience Research’s (Postar) popular coverage and frequency models, which measure only a poster’s ability to be seen. Postar’s system suffers from two deficiencies: while it does measure a viewer’s likelihood to see standard posters, it neither reflects the efficacy of the industry’s new and growing numbers of large-format posters and banners, nor measures the varying ability of posters to deliver crucial advertising and brand recall.

There is now credible research that suggests this is becoming a substantial problem. Research company BJM/NFO Worldwide recently conducted a major study into the advertising and brand recall delivered by eight different poster formats over three separate periods, in order to minimise the skewing effects of the creative work shown on the formats. The crucial finding is stark: the larger the poster format, the greater the advertising and brand recall – irrespective of creative work.

It makes intuitive sense that large format posters should deliver greater recall than smaller ones, but most people are probably unaware of how disproportionate the difference is. For instance, a mega-96-sheet site is 4.5 times larger than a static 48-sheet one, but delivers 16.5 times more advertising recall and 26.5 times more brand recall.

This raises the fundamental question of value: is the greater impact of these larger sites worth the greater cost? As the industry’s measure of value is the cost per thousand people reached, the question comes down to the definition of reach. Should it be Postar’s Visibility-Adjusted traffic count – the number of people with the ability to see the ad? Or should it be the count of individuals who are likely to recall the ad, or, better still, the advertiser’s brand?

Surely recall-based measures are the best gauge of poster efficacy? After all, advertisers want more than for their ads to be seen. They want their messages engaged and their brands enhanced.

We therefore need a major upgrade of Postar. While it has made great strides towards solving the conundrum of outdoor advertising impact, it now needs to embrace the new outdoor formats and the fundamental measures of advertising and brand impact that are crucial criteria for advertisers. Until it does, the Postar system will fall short of providing advertisers and agencies with the data they need to determine media value.

Charles Hamlin is chief executive of Van Wagner UK

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