> For the complete documentation index, see [llms.txt](https://docs.mediarithmics.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mediarithmics.io/audience-and-activation/build-your-audiences/segment-reference.md). # Segment reference What an audience segment is, the properties every segment carries, and the difference between counting a segment and persisting it. ## What this page is for Everything in this section - building, activating, automating, analysing - starts from a segment. This page defines the object itself and the properties shared by every segment type, so the task pages can concentrate on the job rather than re-explaining the object. ## What an audience segment is An **audience segment** is a list of users within your datamart. Segments group users who share the same characteristics (gender, age, area of residence), the same behaviour (categories visited, purchases, purchased products), or the same computed values (statistical algorithms and scores). They can also hold an imported external list of users, or the users touched by a marketing campaign. Segmentation is where audience work begins: it tells you who is buying, reading, or watching what on your channels, and at what frequency. It is also the common currency of advertising - a clearly defined segment ("25 to 35 year old cycling enthusiasts") commands a premium that a loosely defined audience ("people who have used a search engine") does not. ### What a user is A **user** is one person your datamart knows, with every piece of information collected about them, online and offline. A segment is a list of users. The data model calls a user a **UserPoint**, as do some labels and every query: the **UserPoint** column of the segments list counts users, and an OTQL query on users reads `FROM UserPoint`. See [How mediarithmics works](https://app.gitbook.com/s/XSPACE_SETUP/understand-mediarithmics/how-mediarithmics-works#how-your-data-is-modelled-the-userpoint) in the **Setup & Monitor** section. ## Counting is not persistence For a [Query segment](/audience-and-activation/build-your-audiences/segment-reference/segment-types/query-segment.md), counting the segment and persisting it are two separate operations, and confusing them is the most common source of "why is my segment empty?". | | Counting | Persistence | | ----------------- | -------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- | | What it does | Calculates how many users satisfy the segment's conditions and boolean operators | Records each targeted user as a member of the segment, so membership is stored | | When it happens | In real time, on demand | During segment computation, on the segment's evaluation period | | How long it takes | Usually a few seconds (2 to 5) | Depends on the segment size, the refresh policy, and the calculation budget allocated to your account | So a builder can show you a count within seconds while the segment itself is not yet populated. Anything that reads membership rather than a number - activating the segment through a feed, including or excluding it in another segment's query, using it in analytics, exporting it - needs the segment to be persisted first. {% hint style="warning" %} A count is not an activation-ready audience. If you create a Query segment and attach a feed immediately, expect a delay before the first users reach the partner: the feed can only start once the segment has been computed. {% endhint %} ## Segment properties Every segment is created with general information, and optionally with advanced fields. ### General information | Field | Mandatory | What it is for | | --------------- | --------- | ------------------------------------------------------------------------------------------------------------------------------------------- | | **Name** | Yes | Identifies the segment in **Audience > Segments**. A naming convention, and the creation date, help your teams find the segments they need. | | **Description** | No | More detail about what the segment is for. | ### Advanced fields
FieldWhat it doesApplies to
Technical nameA name you choose yourself, mainly used to store the segment's ID in an external system. It can be used as a segment identifier in the mediarithmics API. It must be unique across all your segments.All types
Default lifetimeHow long a user stays in the segment before leaving it automatically. Useful for privacy regulations such as GDPR.List (import), Pixel and Edge segments only
PersistedWhether membership is stored, not just counted. Ticked by default. See Counting is not persistence. Can be changed after creation.Query segments only - every other type is always persisted, and the option cannot be changed
PausedWhen ticked, the segment is not calculated and cannot be used for analytics.All types
Evaluation periodHow often the segment is calculated. Default: 1 day. This is a maximum interval between two computations - a segment may be computed sooner, depending on the platform load when all other segments are computed.Query segments, including those written in OTQL
{% hint style="info" %} **Default lifetime, worked through.** Set a default lifetime of 2 months on a List segment: every user that enters the segment leaves it 2 months later. For an imported list, the default lifetime applies only when no `expiration_ts` was provided in the upload - a value in the file always wins. {% endhint %} ## Untick persistence when you only need the numbers Persisting a segment has a computational cost, so the choice is a real one: * **Untick it** if you only need the segment's stats and dashboard. * **Leave it ticked** if you need to activate the segment through a feed, build other segments that include or exclude its users, use it in user analytics, or export it. ## Where to go next
Segment typesThe nine functional types, what populates each one, and which properties each supports.Segment types
Segment buildersThe three tools for turning criteria into a segment, and who each one is for.Segment builders
Segment capabilitiesMetrics, dashboards, overlap, exports, labels, and the alerts raised on your segments.Segment capabilities
--- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.mediarithmics.io/audience-and-activation/build-your-audiences/segment-reference.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.