Viewability

Viewability measures how many of the people counted near an ad genuinely had a chance to see it. On a public screen, it corrects raw traffic for position, distance, angle and time on screen.

How is it measured?

Online, viewability checks whether a banner actually appeared on someone’s screen long enough to be seen. On digital out-of-home (DOOH) screens, in streets, malls and stations, the question is physical: could the people counted around the screen really see it?

Measurement bodies answer with a set of factors:

• the screen’s size and height,
• the viewing distance and angle,
• how fast people move past (walking, driving, waiting),
• how long the ad stays on screen,
• anything that might block the view.

Those factors turn potential contacts into likely ones. When each contact is weighted this way, the result is often expressed as a VAC, a visibility-adjusted contact.

Example

Illustrative example: a screen in a mall plays your ad 30 times in an hour, with an average of 3 people in front of it each time. That is 90 potential impressions. If the estimated visibility for this screen is 70%, you are left with 63 impressions that really count. A small screen seen sideways from a fast road, with the same traffic, would keep far fewer.

Why it matters when you plan a DOOH campaign

Traffic is not attention. Two screens can claim the same number of passers-by and offer very different real visibility. Ask whether a seller’s figures are raw traffic or contacts corrected for visibility, and compare like with like.

It also guides where you go. A screen people face while they wait (a platform, a checkout queue, a pedestrian crossing) gives your message more time than one they glimpse while driving. Favor those spots, keep the creative simple enough to read in a few seconds, and your impressions carry more weight for the same price.

The same logic applies to your own reporting: a campaign report that states how visibility was estimated is worth more than a bigger number that does not.