Digital OOH now accounts for 46% of global OOH revenue. That is not simply a share story, digital is the primary engine driving total OOH revenue upward, attracting budgets from new categories and driving value to our existing advertisers. The question for our industry is no longer whether OOH can compete with digital media for accountability. It can. The question is whether we move fast enough to prove it.

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‍Digitisation Changes The Unit of Trade

Static OOH retains its value to advertisers with 24/7 exposure and brand positioning against broad demographics. Where digital OOH has shown its increasing value to advertisers and yield to OOH publishers is its flexibility by impression, targeted by time of day and location context – delivered, and verified, in near real time. That shift in the unit of trade is what makes Digital OOH structurally more attractive to advertisers and brings new verticals to our industry, underpinning new routes to market through programmatic trading, and through guaranteed automated trading, where the same rails carry pre-agreed terms and audience commitments.

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Both routes deliver the same thing: the ability to align an OOH investment precisely with an audience strategy and a broader media mix. For media owners, inventory that can be transacted with audience precision commands a premium. The industry is only beginning to capture that premium, and the capture rate will increase as measurement matures.

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Where, Who, Effect

Strip away the technology and the value of any advertising medium rests on three questions: where did the ad play, who saw it, and what was the effect on those who saw it. These are not new questions. What is new is our ability to answer them with the rigour advertisers require.

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Where is now straightforward. Digital screens are geo-located and time-stamped, with proof-of-play logs confirming delivery. This is table stakes.

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Who saw it is harder and more commercially important. It requires audience measurement, estimating, at any given moment, how many people of what profile are in proximity to a given face. For planning, that means models that allow buyers to select locations and dayparts with confidence. For post-campaign measurement, it means delivery data that confirms what was seen against what was booked.

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What effect the ad had, is where the evidence base is now strengthening rapidly. A study published in May 2026 by the OAAA, conducted with Kochava across hundreds of campaigns and seven verticals, found OOH delivered a median performance lift of 20 per cent for in-person outcomes and 14 per cent for digital outcomes - roughly twice the lift recorded for both CTV and broadcast television. OOH was found to precede search activity in 96 per cent of cases and social engagement in 94 per cent. Last-touch attribution has been systematically crediting downstream channels for demand that OOH generated. That misattribution is increasingly difficult to sustain as OOH measurement improves.

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The WOO Global Guidelines: Building the Common Framework

The World Out of Home Organization is publishing its WOO Global Guidelines for OOH Audience Measurement 2.0 at the Global Congress in London. The first edition, published in 2022, brought together eleven national measurement bodies. This edition encompasses 22, from five continents -markets that have built systems from the ground up, markets that have fundamentally rebuilt what was there, and some of the most technically advanced measurement environments in the world.

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What has changed technically in four years is striking. The Impression Multiplier, once a theoretical concept, is now a live commercial instrument with standardised protocols agreed between measurement bodies, media owners, and programmatic platforms. In several markets, continuously collected passive mobility data is now the primary measurement input, tracking hundreds of millions of devices daily. These are not approximations of traditional measurement; they are a different kind of measurement.

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My own reflection, having worked across many of these markets, is that the single most important thing any OOH measurement project can do - whatever its methodology or budget - is design for transparency from the first day. The markets that have grown fastest and commanded the highest advertiser confidence are, without exception, those open to scrutiny.

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The London Congress matters beyond the publication of the measurement guidelines. It is a moment for the industry to demonstrate that OOH is serious about the standards of transparency and rigour that the next decade of trading will require. Alongside the accumulating evidence from studies across the world, the industry is assembling, for the first time, a genuinely compelling case for OOH as a performance medium - not merely a reach medium.