IAB and IAB Europe opened the first-ever joint standard for in-store and travel retail-media measurement to public comment on September 17, with feedback due October 23, 2026. The draft replaces raw “ad play” counts with a footfall-based impression calculation and requires retailers to disclose which of four increasingly imprecise methods they used to estimate audience exposure. Until this standard locks in, every retail media network’s “impression” can mean something different — which means the window to specify how your contracts define and audit that number is now, not after the standard is final.

Retail media has grown into one of the largest line items on a modern media plan, and until now, “impression” hasn’t meant the same thing from one retailer to the next. That’s the gap IAB and IAB Europe are trying to close. On September 17, 2026, the two trade bodies opened a draft in-store and travel retail-media measurement standard for public comment — the first of its kind — with a companion travel media addendum proposing seven-day attribution windows for sponsored placements and thirty-day windows for display.^[1][2]

The substantive change is how an “impression” gets counted at all. The draft replaces ad-play counts — how many times a screen displayed an ad — with a six-input calculation built on footfall: average daily store traffic, store count, campaign duration, number of placements, aisle penetration, and share of voice. The result is an “Opportunity to See” figure, not a confirmed view.^[2] Most stores don’t have sensors to measure who actually looked, so the draft says plainly that the assumptions behind the formula are, in practice, the measurement — which is why it requires retailers to disclose which of four aisle-penetration methods they used, ranked from beacon-tracked (most precise) to a market-study estimate applied at the category level (least precise, and built on the assumption that everyone who bought a product in an aisle saw every ad placed in it).^[2]

None of this is finalized. Comments close October 23, 2026, which means the methodology retailers will use to bill you for in-store and travel media next year is still being written.^[1] That’s an unusual position to be in, and it’s a useful one: once a standard like this locks in, the retailers and networks that helped write it get to define the default, and clients renegotiating after the fact are arguing against an established convention instead of shaping one.

The practical move isn’t to weigh in on IAB’s technical comment period yourself — that’s a standards process, not a client-side negotiation. It’s to make sure your next retail media contract doesn’t just cite “impressions” as if the term is self-explanatory. Specify which measurement tier applies (Ad Play, Gross Impression, Opportunity to See, or Likelihood to See), require disclosure of which aisle-penetration method underlies the number, and build in the right to audit that assumption on a fixed cadence. A standard that clarifies the industry’s math doesn’t help you if your own contract still treats “impression” as a given.

A note on role: We don’t write the measurement methodology or negotiate your retail media rates. What we advise on is making sure your contract’s language keeps pace with a standard like this one — so “impression” has a defined, auditable meaning before you sign, not after a dispute forces the question.

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