> 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/analyze-your-data/compare-segments.md).

# Compare segments

Compare a segment with another segment, or with all your users, on its dashboards.

## Your goal

Understand how one segment differs from another across a set of dimensions - rather than how much they share, which is a different question with a different tool.

## Expected outcome

Your segment's dashboard charts, showing the segment compared with one other segment, or with all the users of your datamart.

## When this is useful

* Sanity-checking two audiences that should be similar, or should not be.
* Comparing a [lookalike](/audience-and-activation/build-your-audiences/segment-reference/segment-types/cohort-lookalike-segment.md) against its seed, to see what the expansion changed.

## Steps

{% stepper %}
{% step %}

### Check that the segment has a dashboard

A comparison is displayed on the segment's [dashboards](/audience-and-activation/build-your-audiences/segment-reference/segment-capabilities/segment-dashboard.md), so at least one must have been set up for the segment, at the `segments` scope.
{% endstep %}

{% step %}

### Open a dashboard tab

Go to the segment you want to compare from, open the dashboard tab to compare on, and click **Compare to segment**.
{% endstep %}

{% step %}

### Choose what to compare with

Click **Select A Segment To Compare With** and choose one segment - you compare with one segment at a time. To compare the segment with all the users of your datamart instead, choose **Compare with all users**.
{% endstep %}

{% step %}

### Stop the comparison

Click **Stop Comparing** to return to the segment on its own. Stop the comparison before you choose another segment to compare with.
{% endstep %}
{% endstepper %}

## Comparison versus overlap

These answer different questions, and choosing the wrong one wastes a step.

| Question                                                    | Tool                                                                                                        |
| ----------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------- |
| "How do these two audiences **differ**, across dimensions?" | A comparison, on the segment's dashboards.                                                                  |
| "How many users do these two audiences **share**?"          | [Overlap](/audience-and-activation/build-your-audiences/segment-reference/segment-capabilities/overlap.md). |

## Crossing segments in a query instead

A comparison only shows the difference. If you want to *act* on the relationship - build a segment of users in A but not B, or in both - use the **Segments** object in the [Advanced Segment Builder](/audience-and-activation/build-your-audiences/segment-reference/segment-builders/advanced-segment-builder.md#reading-the-criteria-panel), which lets you look up a segment by name in order to cross it with other attributes.

{% hint style="info" %}
Crossing a segment inside a query requires that segment to be **persisted** - the query reads membership, not a count. See [Counting is not persistence](/audience-and-activation/build-your-audiences/segment-reference.md#counting-is-not-persistence).
{% endhint %}

## Related pages

<table data-view="cards" data-search="false"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Overlap segments</strong></td><td>The shared-users question.</td><td><a href="/audience-and-activation/analyze-your-data/overlap-segments.md">Overlap segments</a></td></tr><tr><td><strong>Check your audience reach and stats</strong></td><td>Reading one segment's figures properly first.</td><td><a href="/audience-and-activation/analyze-your-data/check-your-audience-reach-and-stats.md">Check your audience reach and stats</a></td></tr></tbody></table>


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