- Out-of-home advertising meaning in plain English
- The main kinds of out-of-home advertising
- Digital out-of-home, or DOOH, explained
- How out-of-home audiences are counted in Great Britain
- Out-of-home advertising and online metrics side by side
- What out-of-home advertising is good for
- Common out-of-home advertising mistakes
- Writing about advertising for other readers
- Frequently asked questions
Out-of-home advertising, or OOH, is advertising shown in public places outside people's homes, such as billboards, bus shelters, transport networks and digital screens in shopping centres and stations. It aims to reach people as they travel, and audiences are estimated using surveys and models.
Billboards on the motorway, panels at the bus stop, screens in the train station: you pass dozens of adverts on a normal day without a phone in your hand. The trade has a tidy name for all of it, and once you know the name, you'll see how much of it there is.
I've pulled this explainer together from the reference material on out-of-home advertising and from UK audience-measurement sources. It's aimed at business owners who've heard the abbreviation OOH and want to understand what it covers and how it's measured.
Out-of-home advertising meaning in plain English
Out-of-home advertising, usually shortened to OOH, is advertising shown in public spaces outside people's homes. The aim is to reach people as they move around: through cities, transport systems, shopping areas and other shared places. Wikipedia calls it one of the oldest forms of mass communication.
Wikipedia says it's also called outdoor advertising, and the two names are used for the same thing. The category stretches to indoor spots too, such as panels in shopping centres, which Ipsos includes in its list of frames.
The main kinds of out-of-home advertising
The reference material divides the sector into four broad groups. Here they are, with the examples each source gives:
| Group | What's in it |
|---|---|
| Billboards and large formats | Big roadside displays and digital billboards on high-traffic routes |
| Street furniture | Bus shelters, benches and other panels in public areas |
| Transit | Adverts on buses, taxis and trains, and in stations and airports |
| Alternative and experiential | Mobile billboards on vehicles or trailers, aerial banners and even people carrying signs |
Ipsos, which works on UK out-of-home measurement, describes the range as adverts on frames running from large roadside billboards down to small bus shelter panels, with boards at bus and train stations, in car parks, on taxis and bus sides, and in shopping malls.
Digital out-of-home, or DOOH, explained
Digital out-of-home uses screens in place of printed posters. According to Wikipedia, digital OOH can run changing content across many locations at once, and it may use real-time data, scheduling, audience analytics and programmatic buying. That means the same screen can show different messages at different times of day.
You'll find digital OOH in transport hubs, shopping centres, streets, airports, sports venues and retail spaces. Ipsos notes that digital panels have made accurate, time-based measurement more important, because an ad on a screen might only be on display for part of an hour.
How out-of-home audiences are counted in Great Britain
This is the part that surprises people. A poster can't count its own viewers the way a website can, so the industry uses survey and modelling methods. In Great Britain the audience measurement system is called Route, which is the industry's agreed measure for out-of-home. The earlier name for it, according to a research news report, was Postar.
Route covers buses, the London Underground and Glasgow subway, rail, shopping centres, airports, cinema foyers, supermarket car parks, service stations, precincts and taxis. According to Ipsos, it works from a travel survey, independent count data used to calibrate the survey findings, and a visibility adjustment. That adjustment reflects the likelihood that someone passing a poster will see it, as opposed to just being nearby.
Ipsos describes its wider approach as five parts: an inventory system storing the details of each frame, a travel survey, a traffic model using vehicle and pedestrian flow data, the visibility adjustment and a data delivery system. For the most detailed work, it describes tracking meters carried by a sample of people over two weeks, which record location within a one-metre radius, second by second.
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Out-of-home advertising and online metrics side by side
If you're used to online advertising, it helps to translate. Online, you can count the times an advert appeared on screen, and I've explained that in my guide to what an ad impression is. Out of home, the equivalent idea is an estimate of how many people had the chance to see a poster, built from the survey and traffic methods above.
- Online: measured directly by the ad system, one event at a time.
- Out of home: estimated from travel surveys, counts and visibility models.
- Both: show an opportunity to see, not proof that someone took notice.
What out-of-home advertising is good for
Because it sits in public places, OOH is naturally suited to reaching people in a particular area or on a particular route, and to building familiarity with a name. It works on glances, so the message needs to be short. Think a few words and one clear image.
That connects to how a business is positioned in people's minds. A poster only has seconds, so it relies on the audience already having some idea of what you stand for. I go into that idea in my explainer on what brand positioning means.
Common out-of-home advertising mistakes
- Putting too much text on a poster that people see for a moment.
- Choosing a site by how big it looks, with no thought for who passes by.
- Treating audience estimates as exact counts. They're modelled.
- Forgetting to say where to go next, such as a short web address.
- Running one design on every format, though a roadside billboard and a station screen are seen differently.
Writing about advertising for other readers
Out-of-home is a corner of marketing with plenty to explain, from measurement to creative. If you work in the field, sharing what you know can help others understand it.
Advertising professionals can look through advertising blogs that take contributor articles.
Frequently asked questions
What does OOH stand for?
It stands for out-of-home. It covers advertising shown in public places outside people's homes, such as roadsides, transport networks and shopping areas.
Is outdoor advertising the same as out-of-home?
Wikipedia treats them as two names for the same thing. Out-of-home is the label the UK measurement sources use, and they include indoor spots such as shopping centre panels.
What is digital out-of-home?
It's out-of-home advertising shown on digital screens. Wikipedia says it can run changing content across many locations and use scheduling and real-time data.
How are out-of-home audiences measured in the UK?
Great Britain uses a system called Route. Ipsos says it combines a travel survey, independent count data and a visibility adjustment.
Can out-of-home advertising be tracked like online ads?
Not directly. Audience numbers are estimates from surveys and models, so they show the chance to see a poster, not proof that someone looked.
