Frequency

Frequency is the average number of times one person sees your ad during a campaign. It is calculated as impressions divided by reach, over a given period.

How is it measured?

Frequency comes from two numbers you already have: impressions (every opportunity to see) and reach (the different people behind those impressions). Divide the first by the second and you get the average.

On digital out-of-home (DOOH) screens, in streets, malls and stations, frequency builds up naturally. People repeat their routes: the same bus stop, the same station, the same shopping street. A screen on that route meets them again and again. Two things push frequency up: your share of the loop on each screen, and how many screens along the same routes carry your ad.

Keep in mind it is an average. Some people pass your screen twice a day, others once in the whole campaign.

Example

Illustrative example: a two-week campaign delivers 60,000 impressions to an estimated 12,000 different people. The average frequency is 5. Double your share of voice on the same screens and, with the same people passing, you get around 120,000 impressions. The reach stays close to 12,000, and the frequency rises to around 10.

Why it matters when you plan a DOOH campaign

People rarely remember an ad they saw once. Repetition in the same place is what turns a passing glance into a message they recall, and that is exactly what a street screen can offer: the same corner, every day.

That is why frequency depends on airtime. If your ad is diluted in a long loop, or bought on screens scattered across the city, the average person sees it too rarely to remember it. Guaranteed airtime on a tight set of screens, where your customers pass every day, gives you the opposite: seen, and seen again.

There is also a ceiling. Past a certain point, each extra repetition adds little. There is no universal number for it, so watch frequency next to reach and adjust once the campaign is running.