> ## Documentation Index
> Fetch the complete documentation index at: https://docs.segmentstream.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom dimensions

> Create custom dimension groupings based on standard dimensions for tailored attribution reports and optimisation portfolios.

You can group sessions and ad platform data by custom dimensions based on standard dimensions such as Source, Medium, Ad Platform, and more.

Custom dimensions let you create reports tailored to your business logic. For instance, you can create a custom dimension to distinguish between paid and non-paid traffic by combining all CPC mediums under a "paid" group and all organic mediums under a "non-paid" group. You can then use this custom dimension in reports to see total metrics for each group.

Custom dimensions can also be used in optimisation portfolios to receive budget allocation recommendations for each custom group.

## Channel custom dimension

The **Channel** custom dimension is predefined and automatically available in all projects. It streamlines analysis of traffic from different sources.

### Default channel groups

* **Google Ads** -- all sessions and ad spend from paid Google Ads.
* **Facebook** -- all sessions and ad spend from paid Facebook.
* **Organic Search** -- all sessions from organic search traffic.
* **Organic Social** -- all sessions from organic social network traffic.
* **Email** -- all sessions from email and newsletter traffic.
* **Referral** -- all other referral traffic.
* **Direct** -- all sessions from direct website access (typing the URL, bookmarks, or untracked sources).

Edit the Channel custom dimension to reflect your reporting requirements. For instance, add new groups for additional ad platforms your business uses.

## How to set up a custom dimension

<Steps>
  <Step title="Navigate to the reports section">
    Open the Attribution reports.
  </Step>

  <Step title="Open the dimensions panel">
    Click **Dimensions**.
  </Step>

  <Step title="Add a custom dimension">
    Scroll down the dimensions list and click **+ Add custom dimension**.
  </Step>

  <Step title="Name your dimension">
    Enter a name for your custom dimension.
  </Step>

  <Step title="Create custom groups">
    Name your first custom group and set the filters that apply to it. For more information on filtering, see [data filtering](/attribution/data-filtering).
  </Step>

  <Step title="Add more groups">
    Click **+ Add group** to create additional custom groups.
  </Step>

  <Step title="Save">
    Click **Save**. Your custom dimension is now available in reports and optimisation portfolios.
  </Step>
</Steps>

<Warning>
  The order of custom groups matters. Filtered data trickles from the top group to the ones below. For example, if you want a "Branded" group for branded CPC campaigns and a "CPC" group for all CPC campaigns, place "CPC" below "Branded". Otherwise, all branded campaigns will be reported within the "CPC" group.
</Warning>

<img src="https://mintcdn.com/segmentstream/d8ABOFFwUMo4IrD2/images/attribution/custom-dimensions-setup.png?fit=max&auto=format&n=d8ABOFFwUMo4IrD2&q=85&s=4b4d6764118ebf8d62b275dc076c3378" alt="Custom dimensions setup" width="2296" height="1624" data-path="images/attribution/custom-dimensions-setup.png" />

## Using custom dimensions in reports

To view data grouped by your custom dimension, select it from the dimension list like any other dimension. Custom dimensions can be edited at any time by clicking the cogwheel icon.

<img src="https://mintcdn.com/segmentstream/d8ABOFFwUMo4IrD2/images/attribution/custom-dimensions-reports.png?fit=max&auto=format&n=d8ABOFFwUMo4IrD2&q=85&s=3a29719942522eca18784aee51ef8887" alt="Custom dimensions in reports" width="2392" height="1622" data-path="images/attribution/custom-dimensions-reports.png" />

Any data that does not belong to any custom group within the dimension is displayed in the "Other" row in reports.

<img src="https://mintcdn.com/segmentstream/d8ABOFFwUMo4IrD2/images/attribution/custom-dimensions-other.png?fit=max&auto=format&n=d8ABOFFwUMo4IrD2&q=85&s=18a76888d5558026aa47e5c69115b5db" alt="Other row in reports" width="2397" height="1388" data-path="images/attribution/custom-dimensions-other.png" />

## Using custom dimensions in optimisation portfolios

Custom dimensions are visible as granularity options during portfolio creation only if they are built from one of these dimensions:

* Ad Platform
* Ad Account
* Campaign
* Campaign Type
* Medium
* Source
* Source/Medium

They will not appear as options if other dimensions are used.

Learn how to use custom dimensions in your optimisation portfolio in the [portfolio setup](/optimization/portfolio-setup) guide.