The most common objection to advertising on real-world screens is also the most reasonable: how do I know it worked? You can't click a billboard. But modern digital out-of-home (DOOH) is far more measurable than its painted-poster ancestors. Here's exactly what gets measured, and how.
Impressions: who actually saw the screen
The base metric for DOOH is the impression — one realistic opportunity for a person to see your ad on a screen. Unlike a web impression (a pixel that loaded), a DOOH impression is modeled from real-world data:
- Anonymized mobile-location and mobility data
- Traffic and pedestrian counts
- Time of day and dwell time near the screen
Industry measurement bodies turn that into an audience estimate — not a guess, but a data-backed model of how many people had a genuine chance to see your ad. It's the same logic that values a busy intersection higher than a quiet side street.
Footfall attribution: did it drive visits?
This is the metric that matters most for a local business. Footfall attribution measures whether people exposed to your DOOH ad were more likely to visit your location afterward.
It works by comparing, on an anonymized and aggregated basis, the later behavior of devices that were near your screens against a control group that wasn't. If the exposed group visits your store at a higher rate, that lift is your campaign's effect. It's not click-perfect, but it answers the real question: did the screen send people through the door?
QR codes and short links: the direct bridge
The simplest, most concrete measurement is one you control: put a QR code or a short link on the creative. Every scan or click is a person who took your screen ad to their phone — a clean, countable action.
This is the easiest bridge from a real-world screen to a digital outcome, and it's why we recommend a strong end card on every campaign (see what makes a great DOOH ad). It also lets you tie a campaign to actual sales if the link leads to a purchase or booking.
Geo-lift studies: the rigorous version
For bigger campaigns, a geo-lift study is the gold standard. You run your ads in some areas (test) and deliberately hold them back in comparable areas (control), then compare outcomes — store visits, sales, sign-ups — between the two.
Because the only systematic difference between the areas is your campaign, the difference in results is a credible estimate of its true, incremental effect. It's the closest thing real-world advertising has to a controlled experiment.
Putting the metrics together
No single number tells the whole story. A healthy DOOH measurement stack usually combines:
- Impressions — reach and how efficiently you bought attention
- Footfall lift — whether exposure drove visits
- QR/link actions — direct, countable response
- Geo-lift — rigorous incremental impact, for larger budgets
Read together, they move DOOH well past "spray and pray" and into accountable media.
The honest caveat
DOOH measurement is modeled, not counted click-by-click, and precision varies by market and data availability. But that's the right trade for screens that can't be skipped, blocked, or scrolled past — and the modeling keeps getting better.
Glo surfaces these signals so you can see what your spend bought, then adjust geography, budget, or creative and run again. To see how this fits a multi-screen plan, read measuring cross-screen lift, or get the cost picture in how much DOOH and CTV cost.