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Your CTV playbook: A guide for linear TV, digital and performance marketers
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Identity resolution is the quiet workhorse powering today’s most effective marketing campaigns. It connects signals across channels and touchpoints to understand where they belong to the same person.
In today’s complex marketing landscape, it is central to how brands drive measurable growth. With identity resolution in place, marketers move beyond isolated interactions to build a more unified view of each customer and the actions that shape performance.
The important caveat is that identity resolution only helps when you can trust the output, because weak matches create weak audiences and misleading attribution, no matter how much data you layer on top.
Deterministic-led identity resolution works much like verifying someone with an ID card, matching data to precise, unchanging information such as name and physical address.
Because the match is highly accurate, brands can unify interactions across digital and offline environments with greater confidence, then tie signals such as site visits, email engagement, app activity and loyalty behaviour back to the same individual.
The impact shows up in plenty of practical ways, and the sections below focus on the ones marketers tend to feel first.
Modern consumers interact with brands in non-linear ways. They browse on mobile, researching on desktop, purchasing in-store and vice-versa. This behaviour fragments data, making it difficult for marketers to see the full customer journey.
Identity resolution bridges these fragmented data gaps revealing critical actions, such as a customer abandoning a cart online but converting later through a retailer ad, and provides a holistic view of behaviour. One of the most powerful real-world advantages of identity resolution is its ability to illuminate customer behaviours that occur outside a brand’s owned channels.
With cohesive identity, marketers can link together customer actions that happen across the open web, in-store environments, and through retailer partners to understand each customer’s path from initial interest to conversion.
This expanded visibility uncovers which channels, messages and moments actually drive purchase decisions. Without identity resolution, critical influences remain hidden: for example, a purchase made through a retail affiliate. By making the invisible visible, identity resolution can bring real-world benefits from optimising strategies, allocating budgets more efficiently, to delivering truly seamless customer experiences.
With Epsilon’s complimentary DiME visualisation tool, you’ll see detailed sales data, online and offline, and know the activity and sales that your marketing is driving.
Once data gaps are filled, brands can build holistic customer profiles that power smarter audience strategies. This includes identifying loyal customers who don't appear in first-party data, for example shoppers who buy in-store with cash or purchase through retail partners rather than direct.
A more complete customer profile opens the door to improving customer loyalty and lifetime value, as customers who feel understood and rewarded are more likely to remain engaged and have a higher affinity for a brand.
Epsilon’s partnership with Dunkin’ created a mouth-watering loyalty programme with offers and incentives that encouraged a 40% increase in member spending YoY.
On average, consumers have five or more identifiers. Often brands unknowingly “count” the same customer multiple times; once for their device ID, then several times for different emails, leading to inefficient spend and message fatigue.
Identity resolution helps identify where the same person appears more than once in your database. This deduplication eliminates redundancy, allowing marketers to reach customers more efficiently, cut wasted ad spend and improve overall campaign efficiency.
Discover how FatFace achieved a provable 3:1 increase in incremental value from its first connected TV campaign through the power of COREid.
Ensuring acquisition campaigns reach genuinely new prospects, not existing customers, is critical because prospecting budgets are often the costliest line item in a marketer’s plan. When brands can confidently suppress known customers from acquisition campaigns, they are able to ensure budget is solely directed toward reaching net-new audiences.
See how Cheerz expanded into open-web video with high-impact large-format ads aimed at high-potential segments, including new parents.
An accurate view of current customers provides a blueprint to find high-value lookalikes. When the source audience is built from truly verified customers the resulting lookalikes are far more predictive, higher value and more aligned to your best customers.
That means prospecting becomes more precise, more cost‑effective and more likely to convert, because you're reaching people who genuinely resemble your most profitable shoppers, not just people who share a device or an email pattern.
Get the inside track on how McDonald’s won a new generation of brand fans, showing up in a culturally relevant way across channels to drive 49% growth in new customers.
With a fuller picture of consumers and prospects, brands can target disengaged customers and understand why they left - whether due to moving out of the market or buying a competitor. Advanced identity solutions also use third-party data to identify when customers are shopping with competitors. Armed with this data, marketers can deploy timely win-back campaigns to reengage lapsed customers and drive sales.
Find out how Decathlon introduced data-driven dynamic creative to maintain 4.3M existing customers and add £1M in incremental revenue.
According to the ONS, as of 2025 29% of UK retail sales now occur online, which means the vast majority are still happening in-store. While online-to-online journeys are well mapped, in-store purchases often remain disconnected from digital media exposure. Digital activity may be driving footfall and revenue, but without evidence, budget naturally shifts elsewhere.
Identity resolution can connect online activity with offline transactions, linking in-store purchases and CRM data back to pseudonymised IDs. Unlocking the in-store view is more than a technical improvement. It helps marketers move away from proxy metrics and towards understanding real behaviour and real outcomes. Media exposures that happen days or weeks before a sale are no longer invisible, and optimisation systems stop rewarding only the most obvious touchpoints.
See how Currys was able to connect TV, online video and display messages all the way to in-store purchase, achieving 56k store visits and a 20% increase in sales.
Identity resolution, combined with AI and machine learning, analyses historic signals to predict future needs. Accurate, unified data is the foundation for effective AI-driven marketing, enabling real-time personalisation and campaign optimisation at scale.
The real-life benefit of understanding your consumer better is delivering more relevant, personalised messages on preferred devices.
Learn how amsterdam&partners accurately identified and reached inbound travellers to the city, achieving over 14.5k site visitors with CTR 20% above benchmark.
Solid identity resolution gives marketers the ability to see the outcome of campaigns at an individual level, rather than relying on averages and assumptions. When you can reliably connect impressions, visits and purchases back to the same person, you learn what genuinely moved behaviour, not just what looked busy in a dashboard. That clarity cuts wasted reach and over-frequency, and it makes measurement sturdier because you’re optimising against outcomes, not proxies.
Over time, the value compounds. You can spot patterns in aggregate across products, channels and audience segments, then shift budget with confidence and prove incrementality.
Most critically, the right identity resolution solution should enable brands to maintain high levels of consumer privacy and evolve as regulations do. Epsilon’s deterministic-led identity resolution uses pseudonymised profiles, ensuring high levels of consumer privacy and compliance with evolving regulations. Privacy is built into every solution, giving brands and consumers peace of mind.
Epsilon’s COREid is designed to create one consistent customer view by matching verified name and address data to a pseudonymised identity that can be used across activation and measurement.
For over a decade, Epsilon has strengthened COREid through trusted publisher partnerships and continuous validation. This creates a live, ever-expanding network that remains the industry’s most accurate, stable and scalable source of identity resolution.
Because the identity is so consistent, it also makes extension feel straightforward: the same audiences and learnings that sit behind a digital campaign can be carried into onsite retail media and loyalty programmes without rebuilding everything from scratch or losing the thread of who you are trying to reach.
The instinct is often to add more data when performance gets murky, but identity has to come first. Once you have coherent identities, the data becomes intelligible and decisioning gets easier, because you’re optimising against real people and real outcomes rather than stitched-together proxies.
If you’d like a practical view of where you can extend existing digital audiences into retail media and loyalty without rebuilding everything from scratch, click the contact us button below and drop us a note and we’ll walk through it with your current set-up in mind.
