---
title: "What is an exposure ledger? | AdBuyMCP"
description: "A single record of advertising exposures across every channel, keyed on whichever of four identifiers a channel can supply, with per-key legal grading."
url: "https://adbuymcp.com/glossary/exposure-ledger"
---

[Home](https://adbuymcp.com/) / [Glossary](https://adbuymcp.com/glossary) / Exposure ledger

AdBuyMCP's own vocabulary

# What is an exposure ledger?

A single record of advertising exposures across every channel, keyed on whichever of four identifiers a channel can supply, with per-key legal grading. They are an opaque household key, a hashed advertising id, a consent-based id and a postcode sector.

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What it means here

## Here is what the term means for a UK buyer

The definition above holds anywhere. Buying media in the UK adds the detail below, including where AdBuyMCP does something different.

The mechanism behind cross-channel frequency deduplication and sequential journeys, and multi-key by design because advertising identifiers are a declining asset: the spine loses precision one step at a time as the finer keys go. The ledger itself never performs an identity join; that happens only in the key-translation service, where the 90-day retention rule is enforced. The ledger is built, and today it is fed only by labelled sample data. A live report proves aggregate delivery, and household exposure needs a key with consent behind it, so AdBuyMCP deliberately does not create identities from a report.

Read next

- [The four keys the exposure ledger uses Goes deeper](https://adbuymcp.com/measurement)
- [The four channels in an awareness plan Channels](https://adbuymcp.com/channels)
- [What UK awareness advertising costs Cost](https://adbuymcp.com/cost)
- [What a fidelity score measures Guide](https://adbuymcp.com/guides/what-a-fidelity-score-is)

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Related terms

## These terms sit next to this one

Most confusion in media buying comes from two adjacent terms being used interchangeably, so these are the neighbours worth reading next.

- ### [Deduplication](https://adbuymcp.com/glossary#deduplication)
  Removing the double-counting that occurs when the same person is reached by more than one channel or placement in a campaign, so that combined reach reflects distinct people rather than the sum of each channel's separate count.
- ### [Frequency capping](https://adbuymcp.com/glossary/frequency-capping)
  Limiting how many times one person or household sees the same advert within a given period, to control wear-out and wasted impressions. It is set per campaign, per channel or, rarely, across channels, and that granularity is what decides whether the cap means anything.
- ### [Identity resolution](https://adbuymcp.com/glossary#identity-resolution)
  The process of deciding that two different identifiers refer to the same person or household, so that behaviour seen under one can be joined to the other.
- ### [Mobile advertising ID (MAID)](https://adbuymcp.com/glossary/maid)
  A resettable identifier assigned by a mobile operating system to a device, used to recognise the same device across apps for advertising. Apple's IDFA and Google's advertising ID are the two that matter.
- ### [Household graph](https://adbuymcp.com/glossary#household-graph)
  A dataset linking devices, identifiers and addresses believed to belong to the same household, allowing a television, a laptop and a phone in one home to be recognised as one buying unit.

Same group

## These terms are also in AdBuyMCP's own vocabulary

These are the terms AdBuyMCP either coined or uses more strictly than the category does.

- [Fidelity score](https://adbuymcp.com/glossary/fidelity-score)
- [Lawful-basis manifest](https://adbuymcp.com/glossary/lawful-basis-manifest)
- [Persona compiler](https://adbuymcp.com/glossary/persona-compiler)
- [Evidence ledger](https://adbuymcp.com/glossary/evidence-ledger)
- [Model Context Protocol (MCP)](https://adbuymcp.com/glossary/mcp)

[All 81 terms](https://adbuymcp.com/glossary)