Identity Resolution: A Complete Guide
What identity resolution is, how it works, and why it has become foundational for addressable advertising in a post third-party cookie world.
What is identity resolution?
Identity resolution is the process of connecting fragmented identifiers — cookies, mobile ad IDs, hashed emails, CTV device IDs, universal IDs — into a persistent view of a single person or household across devices and channels.
The output is an identity graph: a continuously updated map of which signals belong together, and how confident the graph is in each link. Everything downstream in advertising — targeting, frequency capping, suppression, measurement — depends on that map being accurate.
The post-cookie problem
Third-party cookies powered a generation of digital advertising by acting as a de-facto cross-site identifier. As Safari, Firefox and Chrome have restricted them, and as mobile OSes have limited MAIDs, advertisers have lost the shared signal that made audiences, capping and attribution work.
Identity resolution replaces that shared signal with a durable, privacy-safe map derived from consented first-party data and modelled links. Without it, campaigns hit the same users repeatedly, spend leaks into unmeasurable reach, and clean-room activations fall apart at the join step.
Deterministic vs probabilistic resolution
Modern graphs combine both. Each has trade-offs; the right blend depends on the use case.
Directly observed links
- Based on directly observed matches — typically hashed emails, logged-in signals or authenticated IDs.
- High confidence: two IDs are linked because a real user proved the connection.
- Limited to environments where users log in, so coverage is narrower.
Modelled links
- Based on statistical modelling of signals like IP, device, geo and behaviour.
- Extends coverage into the ~90% of open-web sessions where users never log in.
- Confidence depends on signal quality; strong graphs quantify it per link.
Where identity resolution shows up
Audience Building
Unify first-party data across devices and channels to build audiences that scale without duplicating the same user.
CTV & Cross-Screen
Connect connected-TV impressions to mobile and web behaviour so campaigns can be planned, capped and measured across every screen.
Attribution & Measurement
Tie exposures on one device to conversions on another. Without resolution, journeys look fragmented and performance is undercounted.
Retail Media & Clean Rooms
Match partner data to your own inside privacy-safe environments — resolution is the layer that makes those joins possible.
Resolution is a privacy discipline, not a workaround
A durable identity graph is built on consented signals, honours regional frameworks like GDPR and TCF, and treats every input as pseudonymous. That means hashing PII before it enters the graph, running due diligence on every data provider, and giving users straightforward opt-out paths.
ROQAD's graph is consented by design, combining TCF signals with per-provider due diligence — built in Berlin, operated to European standards, deployed globally.
A resolved identity layer for every screen
ROQAD operates one of Europe's largest independent identity graphs — 500M+ unique European IDs and 7B+ cross-device links across the open web, Meta, CTV, Amazon DSP and The Trade Desk. Resolution is delivered as infrastructure: onboarding, enrichment, activation and measurement powered by the same underlying graph.
Talk to us about your identity strategy
See how ROQAD's identity infrastructure fits your web, CTV, retail media and measurement stack.