How to get started with retail media as a brand advertiser

Retail media is the fastest-growing advertising channel in Europe, but most brands run their first campaigns without a clear framework. Here is a practical guide to audience quality, measurement, and budget setup for brands buying retail media for the first time.

TL;DR: Retail media gives brands access to retailer shopper data and closed-loop measurement that other digital channels cannot match. The brands getting the most out of it are not necessarily spending the most, they are the ones asking the right questions before the first campaign goes live. This guide walks through what those questions are.

Retail media is the part of digital advertising that uses a retailer's first-party shopper data to reach customers, either on the retailer's own website and app or across the wider open web and connected TV. For brands that sell through retailers, it is one of the few channels that can link an ad impression to an actual sale, online or in-store.

That sounds straightforward, and the basic concept is. What is less obvious is how to evaluate retail media opportunities, what to ask a retail media partner before committing budget, and how to set up your first campaign so that you can tell whether it worked. Most brands learn these things the expensive way, by running a campaign, getting a report that does not answer their questions, and starting again.

This guide is for marketers and category managers running their first or early retail media campaigns. The goal is to give you a checklist of the things that matter most, in the order they matter.

What makes retail media different from other digital advertising?

The short answer is the data. Retail media campaigns are built on real purchase data from real shoppers, not on inferred audiences or self-reported interests. When a retailer says they can target electronics buyers, they mean people who have actually bought electronics from them, with a known frequency and basket size.

This matters for two reasons.

• First, the audience is more accurate. Behavioural and interest-based targeting on the open web is built on guesses. A user who clicked an article about running shoes might be a runner, or might be a journalist writing about running, or might have clicked by accident. A retailer's shopper data tells you who actually bought running shoes last month.
• Second, the measurement is closed-loop. With most digital channels, you can measure clicks and online conversions but you cannot easily connect an impression to an in-store purchase. Retail media closes that loop because the retailer owns both sides of the data: the ad exposure and the transaction. For an omnichannel brand, this is the difference between knowing whether your campaign worked and guessing.

There are two main types of retail media activity to be aware of. Onsite placements appear on the retailer's own website and app, things like sponsored products, banners, and search results. Offsite placements use the retailer's shopper data to target the same audience across the open web, connected TV, and other digital environments outside the retailer's own properties. Both have their place, and a good campaign usually uses both.

How are brands actually using retail media?

Most brand campaigns in retail media fall into one of four patterns. Understanding which one applies to your objective will save you a lot of time in the planning conversation with your retail media partner.

• Driving incremental sales for a specific product or range. This is the most common starting point. You want to push a particular SKU or category, and you want to know whether the ad spend generated sales that would not have happened anyway. This requires an incremental measurement approach, not just total sales reporting.
• Launching a new product to an existing audience. Retail media is particularly strong here because you can target shoppers who already buy in your category but have not yet tried your specific product. The retailer can tell you how big that audience is before you commit to the campaign.
• Reaching lapsed customers. Shoppers who bought from you six or twelve months ago and have not come back are a high-value audience that is invisible to most digital channels. They exist in the retailer's loyalty data and can be reached directly.
• Building brand awareness with a relevant audience. Connected TV and open-web display are increasingly available through retail media partners, and they let you reach the retailer's shopper base in environments beyond the retailer's own site. This is where retail media starts to compete with broader brand advertising channels.

The point is that retail media is not a single tactic. Decide what you are trying to achieve before you brief the campaign, because the audience build, the placement mix, and the measurement framework will be different for each one.

Where should brands start when planning a retail media campaign?

If you are new to retail media, the temptation is to start with a media plan. Resist this. The first conversations should be about data and measurement, not about placements and budgets. Here are the questions to work through, in order.

• Ask about the audience match rate. This is the proportion of the retailer's shopper database that can be matched to a digital identity and reached with targeted advertising. A high match rate means you can actually reach the audience the retailer is offering. A low match rate means the headline database number is larger than the reachable audience, and you should adjust your expectations accordingly. Retailers using deterministic identity resolution, where shoppers are matched on verified data like name and address rather than email alone, typically have stronger match rates.
• Confirm how outcomes will be measured. Will the report show you clicks and impressions, or will it show you transactions? Will it include in-store sales for omnichannel categories, or only online? Will it measure incremental sales using a control group, or will it count total sales that overlap with the campaign? These are not technicalities, they are the difference between a report you can take to your finance team and one you cannot.
• Understand the audience options before the placements. A good retail media partner will start the planning conversation by helping you define the right audience for your objective, not by showing you a rate card. If the first thing you see is a list of ad units and CPMs, ask to step back and discuss audience first.
• Plan for measurement before launch, not after. Closed-loop measurement requires the campaign exposure data to be linked to transaction data, and this needs to be set up before the campaign runs. Trying to do this retrospectively will produce a less reliable answer and take longer to deliver.
• Start with a defined test, not an open-ended commitment. Your first retail media campaign should have a clear hypothesis, a defined audience, and a measurement plan you have agreed before launch. Resist the pressure to commit to a long campaign before you have seen what the data looks like.

What does good retail media measurement actually look like?

Measurement is where retail media either justifies its premium pricing or does not. If your reports look the same as your display advertising reports, you are not getting the value of the channel.

Good retail media measurement gives you three things.

1. Sales attribution at the SKU level, so you can see which of your products sold to which customer segments.
2. Online and in-store outcomes in a single view, so you are not missing the portion of the response that happened offline.
3. And incremental measurement against a control group, so you can tell your finance team how much of the sales total was genuinely driven by the campaign rather than sales that would have happened regardless.

A practical example. One major electronics retailer running campaigns through Epsilon found that 26% of tracked purchases from a digital campaign occurred in-store. In an online-only measurement model, that quarter of the response would have been invisible, and the campaign would have looked less effective than it actually was. For omnichannel categories, this kind of full-funnel measurement is not a nice-to-have, it is the actual outcome.

The same retailer's brand partners now plan campaigns knowing the in-store contribution will be measured and counted. That changes how budgets are set, how performance is evaluated, and how often campaigns get renewed.

Reach your shoppers through the retailers you already sell with

Retail media gives brand advertisers something the open web cannot: targeted reach against real shoppers, with closed-loop measurement back to transactions, including in-store. Epsilon partners with leading retailers across the UK and EMEA, which means brands can reach those retailers' shopper bases through a single point of contact, with consistent measurement and audience quality across networks.

If you are planning your first retail media campaign or scaling beyond initial tests, talk to our retail media team about which retailer audiences match your objectives and how to set up measurement that will hold up to a finance review.