Outdoor advertising is measured differently from online advertising. There are no clicks and no cookies, but there are traffic figures. With them you can calculate quite precisely how often your campaign can be seen.

Here are the key terms and a worked example from Basel.

The four key terms

Contacts (OTS)

A contact is one opportunity for one person to see the ad. The figure is gross: someone who passes five times counts as five contacts. The industry also calls it OTS, "opportunity to see".

Reach

Reach is the number of different people who saw the campaign at least once. It is always lower than the number of contacts, because many people pass several times.

Frequency

Frequency is how often one person saw the campaign on average. Reach × frequency = contacts.

Share of voice

Share of voice describes the share your advertising has of a surface or a market. On digital screens, several advertisers share the airtime, so your share of voice is the share of time your spot runs. With a scaffolding or facade banner you have the surface to yourself: 100 percent of the surface for the whole campaign.

In a broader sense, share of voice is also used for your share of the total advertising pressure in a category. If you are more visible than your competitors, your share of voice is higher.

All the terms are explained briefly in the glossary.

The basic calculation

For a banner the calculation is simple:

Contacts = contacts per day × 7 × number of weeks

A banner is up around the clock and not shared with anyone. Everyone who passes has the opportunity to see it.

An example from Basel

Take our site at Riehenring 141, a 175 m² scaffolding surface right next to Messe Basel. The site delivers 39'851 contacts per day.

  • Per week: 39'851 × 7 = 278'957 contacts
  • Over four weeks (minimum booking): 278'957 × 4 = 1'115'828 contacts
  • Over eight weeks: 278'957 × 8 = 2'231'656 contacts

You can run the calculation for other sites and periods yourself in the campaign calculator.

From contacts to cost per thousand

To compare sites or media, use the cost per thousand (CPM):

CPM = campaign cost ÷ contacts × 1,000

CPM shows what 1,000 contacts cost you. It lets you compare a scaffolding site with a poster network or an online campaign on the same basis. Keep in mind, though, that a contact is not worth the same in every medium. A 175 m² banner that people look at while waiting at the lights works differently from an ad flashing past in a news feed.

Things to keep in mind

Contacts are not people

On routes people use every day, many see the same surface again and again. That is a strength, because repetition builds recall. But it means reach is clearly lower than the number of contacts.

Traffic is not attention

Not everyone who passes looks. A large format, a good site with dwell time and a simple message increase the share of people who actually notice the ad. See our creative best practices for design tips.

Compare like with like

Use contacts to compare sites and plans with each other. When comparing outdoor with other media, calculate CPM the same way for all of them.

Planning frequency

How often should someone see your message? There is no universal number, but there is a rule of thumb: new or complex messages need more repetition than familiar brands. Longer periods and sites on daily commuter routes increase frequency.

After the campaign: measure the impact

Traffic figures show how many people could see the campaign. Whether it worked, you measure differently:

  • awareness before and after the campaign, for example with a short survey
  • searches for your brand during the campaign
  • visits to a campaign page or to nearby stores

More in How to measure your OOH campaign success. Read about how outdoor works together with other channels in OOH in the media mix.

FAQ

How do you calculate the contacts of an outdoor campaign?

Contacts per day × 7 × number of weeks. At 39'851 contacts per day, that gives 1'115'828 contacts over four weeks.

What is the difference between contacts and reach?

Contacts count every opportunity to see the ad, even if the same person passes several times. Reach counts each person only once.

What does share of voice mean in outdoor advertising?

On digital screens, it is the share of airtime your spot receives. With a banner, you have the surface exclusively. In a broader sense, it is your share of the total advertising pressure in a category.

Want us to calculate the reach for your campaign? Contact us.