Understanding and configuring control groups

November 14, 2023


Personalization Control Group is the ability to randomly exclude a percentage of the traffic from a personalization. The goal of this feature is to make it easier to measure the impact of personalizations, by comparing the conversion rate of the traffic who viewed a personalization and the conversion rate of the traffic that was in the Control Group. Such analytics are not available (yet) in jExperience, but can be done with an external analytics solutions. 

Version and availability

Control groups are fully supported starting in jExperience 2.5.0 and jCustomer 1.7.1.

Configuring a Control Group

Configuring a Control Group can be done when editing the personalization and is available for all types of personalizations (content level personalization, page level personalization, and personalized lists). 

Each personalization has its own Control Group, which means that a visitor can be in a Control Group for personalization and outside for another one.

By default, a Control Group is associated with a visitor profile: if a visitor sees the same personalization across several sessions, the control group value for that visitor won’t change (she/he is either in the Control Group or out). This value is set on the first time the personalization is computed for this visitor. 

There are 3 fields to configure a Control Group: 

  • Status: A Control Group can be active or not. When the Control Group is not active, the percentage of traffic is fully ignored. If a personalization has been running with a Control Group set to active, and then the Control Group is disabled and published, all visitors will see the personalization. 
  • Percentage of visitors to add to the Control Group: The percentage of visitors that will be excluded from the personalization. These visitors will see the fallback variant for content and page level personalization, and the list in the default order for personalized lists. Visitors are added to the Control Group randomly, based on the percentage defined, on the first time the personalization is computed for this visitor.
  • Store Control Group in Session: When active, this option changes the behavior of the Control Group. Instead of being sticky for a visitor profile across sessions, the Control Group is assigned to a session. When the visitor closes his browser and comes back, the Control Group value for a personalization might be different.

Control Group storage

The first time a personalization is evaluated for a visitor, information is stored on the profile to track if the profile is part of the Control Group or not.

In case of a profile merge (with a login for instance), the value of the master profile is taken into account. 
Let’s take the example of a visitor “Charlotte”, that already has a profile associated with her login and is part of a Control Group for a banner personalization. If Charlotte comes back to the website using another device, anonymously, she may see the banner personalization, but if she logs in, the master value of the Control Group will be taken into account.

If the option “Store Control Group in Session” is activated, this information is instead stored at the session level. 

"personalizationStrategyStatus": [
    "timeStamp": "2022-11-18T15:27:58Z",
    "personalizationId": "wempersonalized-8fde39b5-74a5-42cc-b1ea-0e72ccdc94c8",
    "inControlGroup": true