Epsilon has added in-store sales attribution reporting to its Retail Media platform in the UK, linking digital retail media exposure to purchases made in physical shops.
The update addresses a long-standing measurement gap in retail media: brands and retailers can track online outcomes closely but often struggle to connect digital campaigns to sales made at the shelf. UK retail also remains heavily store-based. More than 70% of retail sales take place in physical stores, according to the Office for National Statistics retail sales index.
The in-store attribution reporting is built into the Epsilon Retail Media platform and reconciles onsite activity with in-store point-of-sale transactions. It provides reporting across online and offline outcomes while retaining digital metrics used for eCommerce and onsite optimisation.
Measurement gap
Retail media has expanded as retailers monetise their digital properties and first-party data. Brands have increased spending on sponsored listings, onsite display formats, and offsite media tied to retailer audiences. Even so, measurement has often remained split between online performance reporting and separate store sales analysis.
As a result, brands have relied on assumptions and proxy measures when campaigns influence store visits and shop-floor decisions. This has also made it harder to compare media investments that primarily drive eCommerce with those that shape overall brand and category performance across a retailer's estate.
Epsilon positions the new reporting as a way to provide a single view of online and in-store outcomes in one interface. It says the underlying infrastructure processes large volumes of real-time data and supports deterministic measurement, which typically relies on direct matching rather than statistical modelling. However, it has not detailed the specific data-matching methods.
Reporting metrics
The platform includes metrics designed to separate eCommerce impact from total sales influence. Epsilon will report online return on ad spend to maintain continuity with existing digital benchmarks. It will also report total return on ad spend, combining online and in-store sales performance.
A third metric, halo in-store return on ad spend, is intended to measure sales impact across a brand's in-store product portfolio. This can help show whether media aimed at a small set of promoted items affects sales of related products bought in the same trip or within the same retailer.
The update comes as retailers and advertisers face increased scrutiny over retail media effectiveness. Brands are pushing for clearer evidence of incrementality and more consistent reporting across networks. Retailers, meanwhile, need measurement systems that work across large store estates while meeting privacy and data-governance expectations.
Availability
The capability will be available to all Epsilon Retail Media onsite clients. Epsilon frames it as an option regardless of a retailer's size or retail media maturity, suggesting it will be part of its standard measurement approach rather than a bespoke project reserved for the largest networks.
In practice, in-store attribution requires a retailer's point-of-sale data to be connected with digital signals such as ad exposure or onsite interactions. It also depends on consistent product identifiers and transaction-level data quality that can withstand daily trading and promotional volatility. Retailers vary widely in readiness, particularly where systems have evolved across multiple store formats or technology providers.
"This innovation reinforces Epsilon's pioneering role in retail media," said Esme Robinson, Director Global Platform Solutions and Enablement at Epsilon. "By closing the loop between digital exposure and in-store sales, we're giving retailers and brands the proof they need to invest with confidence and optimise with precision at any scale."
Epsilon is part of Publicis Groupe and operates across data, identity, media, and measurement. Its broader PeopleCloud offering spans customer data platforms, identity resolution, clean rooms, messaging, loyalty, and measurement services, alongside retail media and personalisation tools.
The launch comes as UK retailers step up efforts to build unified views of the shopper journey across digital channels and physical stores. Epsilon says it will deliver the reporting through its platform for UK retail media clients as demand grows for consistent omnichannel performance measurement.