> For the complete documentation index, see [llms.txt](https://help.dscout.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.dscout.com/private-panels/panel-management/require-unique-panelist-phone-numbers.md).

# Require unique panelist phone numbers

To maintain the integrity of your participant pool, you can require panelists to use a unique phone number when signing up to join your panel.

When enabled, this setting checks phone numbers entered by new panelists against those that already exist in your panel. If an existing panelist is associated with the phone number, the new panelist will be prompted to enter a different number to sign up.

{% hint style="info" %}
This setting is enabled by default. If you disable it and enable it again, it will only be enforced for panelists signing up from that point forward. Any existing panelists with duplicate phone numbers will not be affected.
{% endhint %}

**To require unique panelist phone numbers:**

{% stepper %}
{% step %}
In Private Panels, open the **Settings** tab.

![](/files/f4566d07a5fce8579ccf908d1dab79705f6edbca)
{% endstep %}

{% step %}
Under **Panelist governance**, set the **Unique phone number** toggle to **ON**.

![](/files/e6a528954b4c874343aeee5d1a4822888f286403)
{% endstep %}
{% endstepper %}

{% hint style="info" %}
To ensure panelists always enter phone numbers using a standardized format, you can add a regular expression (regex) validation. For more information, see [Validation Regex in screeners](/private-panels/screeners/validation-regex-in-screeners.md).
{% endhint %}

Now, new panelists will not be able to sign up using a phone number already used by another panelist. To allow panelists to sign up with duplicate phone numbers, repeat the steps above and set the **Unique phone number** toggle to **OFF**.

For more information on how you can fight fraud and maintain the integrity of your Private Panels, see [Fighting fraud in Private Panels](/private-panels/panel-management/fighting-fraud-in-private-panels.md).


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