Handling a large control group

When creating your Canvas, you may have expected your audience to split evenly between your control group and your variant group, like in our example below. We can explain why that is and how to fix it!

The group a user joins (either the control group or variant group) depends on their settings. A user will enter a Canvas when they fit all of your criteria defined in the Entry Step. When setting up your Canvas, you define what percentage of users will enter each variant and the control group.

If your control group is large compared to your variant group (and this is not your intent), we recommend that you:

When creating a Canvas with a control group, ensure that all users in the Entry Audience are able to receive messages within the Canvas (i.e. the Canvas contains push and email messages).

Set entry audience push status

Set your entry audience filter to “Is Push Enabled”.

Set entry audience email status

Set your entry audience filter to “is Opted In or Subscribed”.


Let’s imagine the following scenario:

  • A Canvas has a single variant and a control group.
  • The first step of the variant is a push notification.
  • 90% of users were selected to enter the variant, and 10% to enter the control group.

Canvas Example

In this scenario, 90% of the users who enter the Canvas will enter the variant.

If we look back to the Entry Audience (active users), we can see that even though it contains 39.8k users, only 29.1k (73%) of them are push enabled:

Entry Audience

This means that even though we specified 90% of users to enter the variant, not all of those users are actually able to recieve a push notification. These users who are unable to recieve a push notification will still enter the variant regardless.

Still need help? Open a support ticket.

Last updated on December 3, 2020

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