Create and manage a control group

Create control groups for your app, then change their settings or remove them later from each group’s page.

Create a control group

Create a control group to start holding out a share of your users from marketing messages. An app can have several groups, for example one per market. Other groups keep working as they are when you add one. Learn how several control groups work together

Open the Add control group dialog

1. Navigate to Settings > Control groups.
2. Click Add control group.

Name the group

In Name, enter a name that tells the group apart from the others, for example the market it measures. The name is required and must meet these rules:

• Up to 64 characters long.
• No colon (:).
• Unique within the app.

You can rename the group later.

Set the group size

Set the Group size: the share of users held back from marketing messages, from 1% to 20%.

Choose a mode

Mode sets how long the same users stay in the group, and what happens after that.

• Permanent: the group is selected once and stays excluded from messaging until you turn it off.
• Auto-refresh: a new group is selected automatically at the end of each cycle, and the previous one returns to messaging. Set Refresh every to 1 month, 2 months, or 3 months.
• Experiment with an end date: the group runs until the From–To dates you set, then everyone automatically returns to messaging. To must be at least 30 days after From.

To see how each mode appears on the group’s page, see Analyze control group impact.

Scope the control group by country

Optional. Country scope limits which devices are held out. Pushwoosh first selects users by the group size, then holds out only those of their devices that are in the countries you choose. In Countries, select the countries, or leave it empty:

• Empty Countries: every user the percentage formula selects is held out, regardless of location.
• Non-empty Countries: only devices whose system Country tag matches one of the selected countries are held out. A device outside the selected countries keeps receiving marketing messages, even if its user is one the percentage formula selected.

How country scope works per device

• No Country tag, not held out: a device without a system Country tag keeps receiving marketing messages, even if its user is selected and Countries is set. Pushwoosh needs the tag to check the device.
• Per device, not per user: a person with devices in different countries can have some held out and others not. For example, with Countries set to United States of America, their United States device is held out, and their United Kingdom device keeps receiving marketing messages.

Scope the control group by tag

Optional. Tag scope works like country scope above, but by tag value: of the users selected by the group size, only devices with the tag values you choose are held out. If you set both, Pushwoosh applies Countries and Tag together.

1. In Tag, select a string or boolean tag. Country doesn’t appear in this list. Scope by country uses Countries above instead.
2. Choose one or more values that put a user in scope. A boolean tag offers true and false. A string tag suggests existing values and also accepts your own.

• Empty scope tag: every user the percentage formula selects is held out, regardless of the tag.
• Non-empty scope tag: only devices whose value of that tag is one of the values you chose are held out. A device with a different value, or no value at all for that tag, keeps receiving marketing messages, even if its user is one the percentage formula selected.

How tag scope works per device

• No tag value, not held out: a device with no value for the scope tag keeps receiving marketing messages, the same as a device without a Country tag.
• Device tag: each device is checked on its own, so some of a user’s devices can be held out and others not.
• User tag: the value is copied to all of the user’s devices, so either all of them are held out or none are.
• Tag value changes: if a user’s tag value changes, their devices move in or out of scope on the next check. The user stays in the group, and you don’t need to edit it.

A user joins or leaves the group’s audience whenever their tag value changes, and statistics count only users who match the scope today. Scope by a tag that rarely changes, such as market or signup cohort, so the group measures the same audience over time.

The tag scope, together with Countries, applies everywhere the group works: Group size counts only users in scope, messages are held back only from devices in scope, and Export users includes only users in scope.

Check overlaps with other groups

If the countries and tag values you chose match users of another enabled group, the dialog shows a warning that names the overlapping groups. You can still create the group. Users who match both groups are held out by each of them, so the statistics of both groups are skewed.

To avoid an overlap, choose countries that the other group doesn’t cover, or different values of the same tag. Two groups don’t overlap when:

• Both groups are scoped to countries and share none.
• Both groups are scoped by the same tag and share no value.

A group with empty Countries and no tag covers all users, so it overlaps with every other enabled group.

Review and create the group

Check the settings and click Create. Create stays disabled until the name is valid and, if you selected a tag in Scope the control group by tag, until you choose at least one value. The group’s page opens, and the group starts excluding its members from marketing messages right away, following the mode you chose.

You can change the size, mode, countries, and tag later from the group’s page. See Manage the control group.

Manage the control group

Settings > Control groups lists every group of the app with its Audience: All users, or the countries and tag values the group is scoped to. An enabled group whose audience matches other enabled groups shows Overlaps with N groups under its name.

Click the group’s row to reach its own page, where the sections below apply.

Edit the control group size and countries

You can adjust the size of a control group, and the countries it holds out, at any time from its page.

1. Click Control group settings in the top right. The button also shows the group’s current percentage, for example Control group settings: 10%.

2. Choose a new percentage:

   • 3% (Maximum reach): smallest exclusion group for sensitive or high-value audiences.
   • 5% (Recommended for most apps): optimized mix between measurement confidence and user reach.
   • 10% (Higher confidence): larger control group for clearer and more reliable ROI validation.
   • Custom (1%–20%): set a custom control group size for flexible measurement.

   

3. Optional: change the mode.

   

4. In Countries, select one or more countries to limit the control group to, or leave it empty to hold out users across your whole audience.

   

5. Optional: change the tag scope. If you select a tag, Apply stays disabled until you choose at least one value.

6. If the dialog warns that the audience overlaps with other groups, check the overlap before you continue.

7. Click Apply to confirm changes.

What changes when you edit the group

Each setting affects the group and its results differently.

Group size

Membership is recalculated for your whole user base, not only for new users:

• Growing the group adds users until it reaches the new percentage. No one already in it is removed.
• Shrinking the group removes just enough members to reach the new percentage.

This makes results harder to compare with earlier campaigns, so change the size only when necessary.

Other settings

• Mode: the group’s current cycle closes and a new one starts. The users held out stay the same until the next reshuffle, resize, or Auto-refresh rollover.
• Countries: the uplift measurement restarts, because a different audience is now compared. The users in the group stay the same. Only which of their devices are held out from marketing changes.
• Tag scope: the uplift measurement restarts, the same as when you change Countries.

Rename the control group

Renaming changes only the name you see in Pushwoosh. The users in the group, its current cycle, and its statistics stay the same.

1. Click the three-dot menu in the top right.
2. Select Rename.
3. Enter the new name and click Save. The same name rules apply as when you create a group.

Recalculate the group size

Group size shows a saved number that Pushwoosh updates about once a day. Right after you change the group size, or when a lot of new users join your app, this number can be out of date.

To update it right away, click Recalculate next to the group size.

Reshuffle the control group

Reshuffle control group picks a new random set of users, keeping the same percentage. Everyone currently in the group leaves it, and a different set of users takes their place. Use it when the same people have been left out of your marketing messages for a long time.

1. Click the three-dot menu in the top right.

2. Select Reshuffle control group.

   

3. Confirm in the dialog that appears.

Important

Reshuffling changes which users are excluded from marketing and restarts the measurement window for control group analytics: data from before the reshuffle no longer reflects the current group and isn’t included in later comparisons.

Export control group users

Exporting control group users requires the Personal data permission in your role.

Pushwoosh doesn’t tag control group users. Export from this page for a one-off list, or call CheckControlGroupMembership to check a batch of user IDs programmatically.

The file includes only the group’s users within its countries and tag scope.

1. Click the three-dot menu in the top right.
2. Select Export users.
3. When the export finishes, click Download CSV to save the file.

Disable a control group

1. Click the three-dot menu in the top right.
2. Select Disable control group.

Disabling stops that group from holding out any users immediately, and they start receiving marketing messages again, unless another enabled group holds them out. If no enabled group is left, marketing messages go to all users. The group keeps its settings and statistics history. If you re-enable it later without reshuffling, Pushwoosh reproduces the exact same group, since membership is computed by the same formula. To get a different group after re-enabling, reshuffle it.

Segments built on the PW_ControlGroup tag

Pushwoosh doesn’t create or update the PW_ControlGroup tag. Values left in it from before August 25–26, 2026 don’t show real membership, even if your control group stayed enabled.

• If segments, exports, or automations use this tag, rebuild them from Export users.
• When you disable a group, Pushwoosh also clears the remaining tag values in the background.

Delete the control group

Deleting a control group removes it and its configuration permanently. The group stops holding users out, and all its statistics are lost. Other groups of the app keep working. If no enabled group is left, marketing messages go to all users.

1. Click the three-dot menu in the top right.
2. Select Delete group.
3. In the dialog that appears, click Delete to confirm. This cannot be undone.

Keep the history: disable instead

To stop an enabled group without losing its statistics, click Disable instead in the same dialog, or disable the group from the three-dot menu.