If you want to consistently meet customer expectations for more personalized brand experiences—while prioritizing data privacy and security—you need a new way to understand and reach your customers.

And identity resolution may be just the tool you’re looking for.

This guide will help you understand what identity resolution is, why it’s important and how it works.

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What is identity resolution?


Identity resolution is the ability to recognize an individual person, in real-time, by connecting various identifiers from their digital interactions. ID res matches these identifiers across devices and touchpoints to create a single customer profile.

For instance, a prospective customer could be engaging with your brand on their phone, as well as their desktop, and their tablet.

They could sign into an account they hold with you, or they could engage as a guest.

Or, they may read your newsletter, engage with you on social media, and purchase from your website.

Identity resolution links all of these interactions to the real person who’s engaging.

By linking all of these separate interactions to a single person, you’re able to get a more complete view of their engagement with your brand—and create more personalized experiences.

But it’s not just about the device or the person identifier. True identity resolution goes beyond devices to recognize and understand the person in real time, in the moments that really matter.

Single customer view, achieved.

Deterministic identity resolution vs. probabilistic resolution

What’s the difference between deterministic and probabilistic identity resolution? It’s a matter of how confident you are in the data matching.

Deterministic matching is based on what you know to be true. There are no assumptions or inferences involved about who someone is or what identifiers belong to them. Deterministic identity resolution therefore offers a high degree of confidence that you’ve resolved the right data to each customer profile.

Probabilistic matching is based on what you predict to be true, based on predictive modeling. With probabilistic identity resolution, you will have varying levels of statistical confidence, based on which models have been used in the process.

For marketers, the main tradeoff between these two methods is accuracy versus scale. Deterministic identity resolution offers high accuracy, but you sacrifice a bit of scale.

Probabilistic identity resolution allows you to reach a lot of people, but you sacrifice accuracy—they may not be the people you want to reach.


Why is identity resolution important for marketers?

Identity resolution is getting popular mostly because consumers’ have been getting more concerned about data privacy. In response, governments are enacting legislation like GDPR and CCPA to protect and reign in marketers’ use of consumer data.

Taken together, GDPR and CCPA provide an unprecedented opportunity for marketers to get serious about privacy and data security. And the tech industry is responding in kind.

Since tech giants like Apple and Google announced the phasing out or “deprecation” of common identifiers, marketers have been scrambling to figure out what “cookieless advertising” will look like. Soon, we’ll no longer be able to rely on identifiers like third-party cookies or mobile ad IDs (MAIDs)—like Apple’s Identifier for Advertisers (IDFA), and Google’s Google Advertising ID (AAID).

Most brands have been dependent on these identifiers to identify, understand, and reach their customers. As they continue to disappear, brands without a contingency plan are losing visibility into customer interactions, and they’re losing the ability to accurately and persistently reach these customers with their messaging.

In response, some brands are reverting back to less effective contextual advertising. But highly targeted and highly personalized marketing is still possible—it just requires a strong first-party data strategy plus a privacy-centric identity resolution solution.

How does identity resolution work?


The process of identity resolution starts with all of your first-party data sources. This could include data from your CDP, customer relationship management (CRM) platform, customer database, email platforms, and more.

This data is all resolved and enriched against an identity graph.

What is an identity graph?

Before we take a look at the process of identity resolution in more depth, it’s helpful to understand what an identity graph is—and it’s not really a graph at all.

An identity graph is a database of all identifiers matched with privacy protected customer profiles. You can think of it like billions of contact fragments—names, device IDs, website visits, transactions, etc.—with connections between them. A grouping of fragments and the connections between them represent a person, formed in the graph.

The fragments—or identifiers—are tied to the customer profile with various degrees of certainty. There’s no standard model for an identity graph, so each vendor will use their own selection of foundational PII, non-PII, and name matching methods.

Common identifiers in an identity graph may include:

There are often also undeclared identifiers, such as:

  • Membership in an email or subscriber list
  • Demographics
  • Purchases/transactions
  • Visits to online news sites
  • Surveys
  • Voter registration
  • Motor vehicle records
  • Other financial and digital behaviors

The identity resolution process relies on this identity graph to associate pieces of information with a person, learn more about that person, and reach that person across devices and channels.

Let’s say Julie provided her email address on your website in exchange for a coupon. However, she ended up visiting the store to make the actual purchase. The identity graph would show a connection between Julie’s email address and her credit card transaction so that you could resolve those two interactions into a single customer.

Then, the graph could provide additional insights about Julie, such as past purchases (with your brand and other brands), household composition, personal interests (she’s definitely into DIY home improvement), etc. The graph also provides insights on places you can reach Julie, such as on websites she frequents, apps she uses, and more.

Now, you have more context and can reach Julie in more places, recognize her immediately when she comes back to your site, and accurately measure the impact of each interaction with her.

The identity resolution process



Unify customer and prospect data by linking complete or fragmented identifiers.


Append new insights to understand the whole person.


Reliably reach customers in all the channels they frequent.

1. Resolve identity

The first step is to identify real people by resolving your identifiers (all of those contact fragments) to a known person.

Your identity resolution tool ingests or onboards the data sets you already have on your customers:

  • It may be a full name, email, and physical address from their online purchase.
  • It could be a phone number or Twitter handle they used when chatting with customer support.
  • Or perhaps it’s just a secondary email address this person used to sign up for your newsletter.

People represent themselves differently depending on how they interact with your brand. They may provide any number of identifiers, and while they’re all the same person, your systems register them separately.

Identity resolution tools collect this information from the various silos in your martech stack and align it with the identity graph—matching identities to identifiers, eliminating redundancies, and providing a distinct, persistent ID.

Now, every time this person interacts with your brand, you can recognize them based on the ID.

2. Enrich customer profiles

With identity resolution, you can transform a single identifier (like an email or a phone number) into a whole person.

Data enrichment through the identity graph provides additional details and context about each person in your database. Once you have connected all of your data to a real human, the graph can provide you all kinds of colorful details about who this person is (while protecting PII, of course).

This enrichment makes it easier to segment your audience effectively and target the right people with your marketing efforts.

Plus, the best data enrichment is in real time. That means when a new visitor shows up on your website, you’ve got immediate context about who they are and what they’re interested in—even when they’re unauthenticated.

3. Activate in market

The activation phase is where it all comes together.

You’ve resolved your data into real people.

You’ve enriched it to learn more about each person and make stellar segments.

Now, you can reach each person wherever they are online by using mobile Ad IDs, hashed emails, postal addresses, social handles, etc. You can push highly relevant messaging to these audiences through the channels of your choice—such as data management platforms (DMPs), demand side platforms (DSPs), media partners, etc.

You can also use identity resolution to recognize customers as they show up on your owned properties and deliver personalized experiences. And because each interaction (including transactions) is logged against a persistent ID, real-time, omnichannel measurement is a breeze.

5 benefits of identity resolution


Unify first-party data for a single customer view

Identity resolution allows you to connect and consolidate identities from across your organization’s data silos. Instead of identity fragments floating around across your online and offline channels, you have a single view of each person—that’s more complete and accurate than before.

Create consistent, personalized experiences

When you can identify prospects and customers, you can communicate with them like people—not devices—personalizing their experiences wherever they’re engaging with your brand. You can also use identity resolution to enrich your customer profiles with thousands of unique data points. And the more you know about each person, the more personal you can get.

Reach the right people in more places

Identity resolution lets you append identifiers like hashed emails and mobile ad IDs (MAIDs) to your customer profiles. These identifiers help you to connect with the right customers in more of the places they hang out—which can greatly improve your ROAS.

Measure accurately across channels

Optimize the effectiveness of marketing campaigns, from exposure to conversion, by assigning each person a unique person identifier (like our PersonID). As customers progressively engage with your brand, it stays persistent—so you get an accurate view of your performance across the customer journey.

Protect PII and comply with privacy regulations

The right identity resolution provider handles the PII, so you don’t have to. Instead, you use your unique person identifiers to follow customers along their journey, across your enterprise, or with third-party partners—without accessing or transferring sensitive information.

See it in action—3 identity resolution use cases

What does it all look like when it comes together? Here are a few common use cases—but there are nearly infinite possibilities for putting identity resolution to use across various industry verticals.

1. Improve ecommerce conversions

Identity resolution lets you see, in real-time, who is actively browsing on your website. And when you can recognize your customers, you can personalize their content based on their historical interactions with your brand.

No brand history? No problem. Identity resolution also informs your next-best action for unauthenticated visitors with relevant third-party data (remember that enrich step?).

For example, transaction data may show your unauthenticated visitor is likely in-market for running shoes. Show her your promotions on sneakers and other running gear instead of the promotion for professional footwear.

Brands using identity resolution on their website see a 32% average increase in unauthenticated recognition and a 13% increase in conversion after personalizing content and guiding his or her shopping experience.

Learn more about increasing ecommerce conversions.

2. Improve retention and loyalty

There’s no getting around the fact that today’s brands win on customer experience. You’ve probably heard the stat that 86% of buyers will pay more for great customer experience, but it’s worth repeating.

Conversely, 32% say they’ll walk away from a brand they love after a single bad experience.

Achieving a single, unified view of the customer through identity resolution allows you to understand each customer more completely in order to provide them with better experiences—and ultimately increase the likelihood they’ll come back again.

Let’s say Renee recently bought some size 10 boys pajamas, and shows up on your website a short time later. Don’t bother showing her more boy’s pajamas—instead, serve us some related items in the same category, like slippers, or more boys items you have available in size 10. And eleven or twelve months later, use your persistent ID to reach her with offers for size 12 boys pajamas.

These are the kinds of personalized experiences that increase loyalty and customer lifetime value.

3. Reduce wasted ad spend

Spray and pray has never been a good strategy (and contextual marketing is only a bit better!). Duplicate records plus poorly defined audience segments mean your message is often wasted on the wrong person and/or the wrong channel.

Unifying your customer and prospect data helps you identify individuals across multiple devices, channels, and platforms. This process eliminates duplication and waste by ensuring you’re not targeting the same person multiple times.

It also allows you to find the best possible targets for your marketing and understand which message will resonate best.

Let’s say you’re an auto dealership, and you have a CRM full of prospects that have visited in the past few months. By onboarding this data and aligning it to the identity graph, you can determine which of them:

  • Are most likely to be in the market for a new car
  • May need to upgrade to accomodate a new baby
  • May need a vehicle with space for a dog
  • Etc.

If Renee has a 2011 Corolla and just had a new baby, show her ads for your crossover SUV. John, on the other hand, has just graduated from high school and never owned his own car—show him ads for a no-frills sedan with free financing.

You can also gain incremental touchpoints to reach these ideal customers like Renee and John. We see clients increase their omnichannel reach by 5X to increase media performance.

You may have only had John’s name and email address. Identity resolution, however, shows you that he frequents the Huffington Post website, often checks his Weather Channel app, and he spends an inordinate amount of time streaming TV on his Roku. Now, you can make sure your messages show up when John visits these additional channels (yes, including CTV).

When you have the data to define highly segmented audiences and target exactly the right people with relevant messages, you can greatly reduce wasted ad spend—and increase your ROAS.


Get more inspiration: 6 creative identity resolution use cases you’d never imagine.


Identity resolution software vs. customer data platforms


There’s a tool for that! Actually, there are lots of tools that claim to perform identity resolution.

Identity resolution software is defined as software that integrates consumer identifiers across channels and devices in a way that is accurate, scalable and privacy compliant to create a persistent and addressable individual profile.

Identity resolution isn’t meant to replace other martech solutions, such as CDPs (customer data platforms)—they are highly complementary tools.

Many people mistakenly believe CDPs perform identity resolution (and many CDPs allow them to believe it). In reality, a customer data platform acts as a repository for all of your known customer data.

Identity resolution goes a few steps further to:

  • Align your disparate first-, second-, and third-party data sources into a true unified customer view
  • Enrich your existing data with additional details and context
  • Identify unauthenticated individuals that visit your owned properties
  • Accurately reach your customers in all of the channels they frequent

Exciting opportunities with identity

It can be tough to be a marketer these days—but it can also be exciting.

A privacy-centric identity resolution solution solves for some of today’s most pressing challenges (bye, cookies!), while opening up new opportunities we’ve never seen before (hello, real-time customer recognition).

Learn more about how identity resolution can revolutionize your marketing and customer relationships.

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