Why impression-based buying is the next evolution of DOOH

There’s little question of the impact out-of-home (OOH) advertising makes on audiences - whether it be large-scale, one-off brand activations such as Cristiano Ronaldo’s Time Square takeover, or smaller promotions on bus stops or within retail environments. The ongoing effectiveness in OOH is reflected in the continued growth in ad budgets, with the global advertising expenditure for OOH set to reach $45bn by 2024.

The growing popularity of digital out-of-home (DOOH) has opened further opportunities for brands to grab audience's attention, most notably with 3D digital billboard promotions. However, it is the expanding usage of programmatic DOOH that enables marketers to more effectively reach their target audiences. By leveraging unique audience data sets, programmatic DOOH is by its very nature an audience-centric technology. However, in order to truly harness programmatic DOOH, both advertisers and media owners need to understand the value of impressions-based purchasing.
 

Becoming part of the bigger picture

Within other advertising environments, including digital display, social and mobile, impressions are a standardised and widely used metric in order to buy and sell ad slots programmatically. With promotions delivered on a one-to-one basis, impressions allow marketers to buy promotions in environments where they are guaranteed to be seen by audiences. As programmatic has matured, these metrics have been further fine-tuned, with marketers now able to purchase promotions based on models such as quality cost per mille (qCPM).

However, for DOOH, impression-based buying was challenging due to its one-to-many nature. Previously, DOOH and other one-to-many channels such as connected TV (CTV) were siloed from other channels with their own standardised measurement, ratings, and audience insights. As marketers have looked to approach marketing plans in a more holistic way, the demand for a more universal, impressions-based audience metric has grown.
 

Defining DOOH impressions

Within online environments, impressions can be attributed relatively simply. Google, for instance, counts an ad impression as ‘each time a creative is downloaded in the user's device and has begun to load’. With one-to-many channels however, the formula to attribute impression numbers is more complex.

Programmatic DOOH’s data-centric approach is vital to enabling impression-based buying. Media owners and advertisers alike can benefit from a wealth of data points, including traffic, audience mobility, density and dwell times. On top of this, several advancements have been made through innovation of ad tech that facilitates programmatic DOOH advertising and has provided a much more accurate view into audience measurement metrics such as reach and frequency.

Central to this, an “impression multiplier” collates a number of these data inputs to better estimate the number of impressions that are attributed to one single DOOH ad play during a given hour of the day. With DOOH being a one-to-many channel, it is critical that audience measurement is computed with a formula that is customised for each market. Variables such as the number of impressions assigned to an ad play, qualified traffic and dwell time all help to formulate a more accurate view of impressions for a single screen. For buyers, this enables budgets to be maximised towards audience reach, and not just the total number of ad plays. While for media owners, this data allows them to more accurately price ad slots and provides highly valuable screen level data.

While impression multipliers enable more effective planning, programmatic DOOH has many beneficial features that allow for advertisers to more effectively manage campaign budgets and ROI. Data such as real-time audience patterns, behavioural traits, and footfall allow marketers to redistribute budgets to optimise performance of campaigns. When utilised alongside the machine learning and automation present in programmatic DOOH, marketers can ensure maximum impressions gained and maximum impact made on audiences.

As more marketers look towards omnichannel campaigns to ensure they reach audiences across multiple environments in a cohesive manner, it is imperative that the wider DOOH industry collaborates to create standardised guidelines and approaches to audience measurement.