How audiences are counted
In the U.S., Geopath is the industry's audience-measurement organization. It estimates how many people notice each unit (not just pass it), using traffic counts, travel surveys, mobile location data and visibility research (size, angle, distance, illumination). Its outputs include:
- Impressions — estimated number of times people see the ad.
- Reach — unique people exposed at least once.
- Frequency — average number of exposures per person reached.
- GRPs / TRPs — impressions as a percentage of the market (or target audience) population.
Other markets have their own bodies, such as Route in the UK.
Attribution methods
| Method | How it works | Good for |
|---|---|---|
| Mobile location attribution | Compares store/website visits from devices seen near the ad vs. a control group | Foot traffic, app installs, web visits |
| Brand-lift surveys | Survey exposed vs. unexposed people on awareness, consideration, intent | Brand campaigns |
| Search & web lift | Track branded search and direct traffic in the ad's markets vs. control markets | Any campaign |
| Matched-market tests | Run OOH in some markets, hold out similar ones, compare sales | Sales impact |
| Retail & sales data | Retail-media or POS data tied to screen exposure | CPG, retail |
| Media-mix modeling | Statistical models that estimate each channel's contribution | Large multi-channel advertisers |
Simple tracking for any budget
- Unique phone number on each board or format.
- Vanity URL or promo code (e.g., brand.com/drive or code EXIT42).
- QR codes where people are stationary — transit, shelters, place-based, kiosks.
- "How did you hear about us?" at checkout and on forms.
- Before/after comparison of branded search, direct traffic and store visits.
- Geo-split — compare zip codes near the boards with similar zip codes without them.
Effectiveness benchmarks
Industry studies widely cited by OAAA and vendors report strong recall and action from OOH — for example, high shares of consumers say they noticed a digital billboard in the past month, and many report searching online or visiting a business after seeing an outdoor ad. Treat vendor statistics as directional, and set up your own tests.
Recommended tools
CallRail ↗
Unique tracking phone numbers per board or format to prove which placements make the phone ring.
QR Code Generator PRO ↗
Dynamic QR codes with scan analytics for transit, shelters, kiosks and place-based ads.
Uniqode ↗
Enterprise QR codes with scan tracking and editable destinations after printing.
Some links are partner links; we may earn a commission at no extra cost to you. All tools
Price out your campaign
Plug in impressions, CPM and flight length to see a realistic budget.