CTR (Click-Through Rate)

Click-through rate (CTR) is clicks divided by impressions, expressed as a percentage. A web display banner with 500 clicks per 100,000 impressions has CTR 0.5%. CTR is the foundational performance metric in search and web display advertising — both are click-intent channels — and a marginal metric in video, CTV, and DOOH where there's no click target.

For DOOH, CTR is essentially zero (the screen is not clickable) and the relevant lower-funnel measurement is foot-traffic lift, cross-device attribution to a mobile app open, or a brand-lift study for upper-funnel campaigns. The IAB's DOOH Attribution Framework standardizes three measurement modalities: foot-traffic lift via mobile-location panels, online lift via cross-device match, and brand-lift via survey.

For CTV, CTR is technically possible through QR codes on screen, but in practice the action is "phone scans → URL opens" which is its own metric and well below web-display CTRs. Most CTV measurement skips clicks entirely and goes straight to attribution.

Buyers running multi-channel campaigns should not collapse all formats to CTR — using CTR to compare DOOH to search will always make DOOH look broken because DOOH isn't a click channel. The right metric for DOOH is the appropriate lift study or attribution model for the campaign's stage.