In-Store Sales Attribution: Closing the loop on retail media

Retail media is one of the fastest‑growing channels in advertising, but until now one critical question has remained unanswered: Does retail media actually drive sales in store?

Epsilon is answering that question with the launch of in‑store sales attribution within the Epsilon Retail Media platform. This capability enables retailers and brands to directly measure how onsite digital retail media drives real‑world, in‑store purchases, delivering true closed‑loop retail media measurement.

Why in‑store sales attribution matters

The UK is a highly store‑led retail market, with more than 70% of retail sales still happening in physical stores (ONS). Yet retail media measurement has historically focused on digital-only outcomes — impressions, clicks and ecommerce transactions.

That disconnect has created a major challenge for retail media networks:

• Retailers struggle to prove the true value of their retail media inventory
• Brands rely on assumptions rather than confirmed in-store impact
• Media investment decisions are made without a full view of performance

Without a reliable way to link digital exposure to in‑store sales, retail media measurement has remained incomplete. Epsilon’s in-store attribution closes that gap.

Read more about the challenges of incomplete offline data.

From digital retail media to in-store sales – in one platform

Epsilon’s in‑store attribution is built directly into the Epsilon Retail Media platform. It automatically connects onsite digital activity with in‑store point‑of‑sale data, creating a single, unified view of performance across the shopper journey.

Now retailers and brands can clearly see how retail media campaigns influence purchasing behaviour beyond the screen and into the store.

Designed for brick-and-mortar reality

Epsilon’s approach to in‑store attribution is powered by a proprietary data infrastructure designed to process large volumes of real‑time data. Combined with Epsilon COREid, this enables deterministic, scalable measurement of in‑store impact — a critical requirement for modern retail media networks.

Read more about how Epsilon’s identity-led approach drives effective retail media.

For retailers, this means the ability to:

• Prove the real‑world value of retail media networks
• Strengthen advertiser confidence and long‑term investment
• Differentiate their retail media offering with transparent measurement

In a market where physical retail remains dominant, in‑store attribution is no longer optional, it’s essential.

Clear, transparent omnichannel measurement

To support better decision‑making and accountability, Epsilon now delivers a new suite of omnichannel retail media metrics, including:

Online ROAS
Maintaining continuity with existing digital / ecommerce benchmarks

Total ROAS
Omnichannel measurement capturing both online and in‑store sales impact

Halo Instore ROAS
Measuring a campaign’s influence across a brand’s full in‑store product portfolio

Together, these metrics provide a more complete view of retail media performance without sacrificing the digital performance insights advertisers rely on.

What this means for retailers and brands

By linking digital retail media exposure directly to in‑store sales, Epsilon is delivering true closed‑loop measurement across online and offline channels.

• Retailers gain stronger proof points to grow and monetise retail media networks
• Brands gain clarity on in‑store sales impact, enabling smarter optimisation and investment

Importantly, in‑store attribution can be made available to all Epsilon Retail Media onsite clients, regardless of size or maturity.

Setting a new benchmark for retail media measurement

With the launch of in‑store attribution, Epsilon is setting a new benchmark for retail media in Europe, empowering retailers and brands with the clarity, confidence, and proof required to invest smarter and grow faster.

As retail media continues to evolve the ability to measure every sale, wherever it happens, will define the next phase of growth.