Are your out-of-home ads working? Measuring ROI in OOH

July 28, 2021Samantha Brault

One more time for the people in that back row: in terms of advertising spend, digital out-of-home (DOOH) is one of the fastest-growing media channels right now, with more brands than ever turning on to the unique capabilities of the format. 

When we speak to advertisers who are considering incorporating DOOH into their media plans, we’re often asked how the effectiveness of DOOH campaigns is measured. 

Many brands approach DOOH expecting a measurement standard equivalent to the online impression or Gross Rating Point (GRP). However, DOOH media is different: it doesn’t just play in a browser, on TV or on an app, but appears across different types of displays around the world from escalators to roadside billboards, wayfinding kiosks to airport lounges, making it more difficult to establish fully standardized metrics. 

Another key difference is that when you load a web page, ads are served in a one-to-one environment, so ‘one ad served’ equals ‘one impression’. By contrast, DOOH advertising is served in a one-to-many environment. A single OOH ad has the potential to achieve hundreds of impressions. 

But how can we really know that? And what does a DOOH impression look like anyway?

Fortunately, there are several reliable and rigorous methods of measurement available to help make a strong case for DOOH and these have been bolstered even further in recent years through the growth of programmatic transactions in the DOOH space. 

The basics of DOOH audience measurement

An OOH impression is defined by the total number of times people are likely to notice an ad on an out-of-home display. However, DOOH can draw upon a range of different data sources for measurement purposes, depending on a screen’s individual environment.

For example, in relation to auto traffic, media owners can work with local municipalities and transport authorities to attribute the number of cars to specific ad faces. Many organizations take it a step further with location and movement data that helps us understand how, why, and where people are travelling when they are passing DOOH screens. 

This data allows us to qualify exposure metrics like proximity, dwell time and establish robust ‘opportunity to see’ (OTS) zones by environment. 

In addition, many media owners are partnering with companies that deploy AI and recognition technology to provide even more information on the cars and/or pedestrians passing their screens, while maintaining viewer anonymity. 

Drawing on statistical analysis, independent research firms like Neilsen and GeoPath can also accurately estimate the number of eyes on a designated screen at any particular day, time or location. 

Impacts on brand and performance metrics

OOH is fundamentally a brand awareness medium. There’s lots of evidence that OOH campaigns can have a significant positive impact on metrics such as brand awareness and brand recall. 

But in some cases, marketers also want to measure the impact on performance metrics of adding DOOH to their other channels. For example, location data pulled from opt-in audiences can be used to measure the impact of an OOH exposed audience on footfall traffic to a specific store location. A similar technique can be used to measure impact on sales, by comparing point-of-sale data from stores near a campaign screen location to POS data from other stores.

In many ways, the full ROI of DOOH is still emerging, however, it is already clear that when utilized as a part of an omnichannel campaign, DOOH can significantly amplify the impact of other campaign channels. Recent research suggests: 

  • DOOH can increase reach by as much as 303% when added to mobile or web messaging; 
  • DOOH drives four times more online search and social media activity per ad dollar spent than TV, radio, or print; 
  • DOOH ads make it 46% more likely for consumers to engage with a brand on mobile. 
  • nearly 4 in 10 adults surveyed (38%) in the US say they have visited a Facebook Page or posted on Facebook after seeing an OOH ad, and 25% have posted to Instagram.