Common knowledge, not private intel

In recent weeks I've read a couple of posts that, together, say something our industry seems to be avoiding.
 
Nick Bell at Billups recently made the case that impressions are generally a surrogate – initially for awareness, then perception, then propensity to buy, and finally actual sales. If we lose track of this, we risk pursuing a delivery number that actually does nothing for the metric it’s meant to represent.
 
G Douglas-Kilgannon made a related point about the risk of treating impressions as “interchangeable”: two ads can attract identical levels of attention for the same CPM and still not actually be worth the same. One might be viewed “one to one”, in isolation, on a screen only you can see. The other could be watched by millions simultaneously, with everyone aware that everyone else is also viewing.  The latter message becomes common knowledge, not private intel.
 
This matters because it affects how consumers react socially: how they reference it, recommend it, buy it, in the confidence that others will respond in the same way. We’re much more likely to endorse a brand that’s been on every bus shelter, or the most iconic billboards in town. That “public confidence” is a real-world manifestation of what “fame” actually is – and a large part of why famous brands are chosen by default, together with why they can charge more for it.
 
All of which reinforces Nick’s concerns about relying too heavily on surrogate measures of achievement. Impressions could be even less related to the outcomes we’re actually seeking, depending on whether the exposure was personal or shared. Around 80% of UK adspend is now online, and most digital coverage lands on personal screens, one viewer at a time. All of which delivers reach, but without the personal confidence that anyone else saw it too. That’s the difference between the private screen and the public, OOH one.
 
Public, simultaneous, unmissable exposure, whether on a massive banner, screens in student unions, or a fleet of taxis, isn’t just reach. It’s a platform that transforms impressions into what every surrogate in the chain is actually trying to approximate – confidence, intent, and real-world action.
 
If we’re serious about measuring what actually matters, we need to look past impressions and start valuing this difference, not just talking about it.