What’s causing the missing email-activity data for A/B (split-test) campaigns?

Mailchimp’s API does not return email-activity data at the parent campaign level for A/B or multivariate campaigns. This isn’t a problem with our integration, it’s intentional behavior based on how Mailchimp structures these campaigns.

How does Mailchimp structure A/B test campaigns?

An A/B test in Mailchimp consists of a parent campaign and several child campaigns. Each version of the test, such as different subject lines or different content, is delivered as its own child campaign with its own campaign ID.

Because of this:

• The parent campaign is never actually sent to recipients.

• Only the child campaigns have delivery and engagement.

• Mailchimp does not aggregate open/click activity back into the parent.

Why doesn’t the email-activity API endpoint return data for A/B campaigns?

The endpoint that normally returns email-activity only works for campaigns that were actually sent. Since the parent of an A/B test is not sent, Mailchimp does not return activity for it.

Will Mailchimp add parent-level A/B test activity to the API?

We are waiting on clarification from Mailchimp’s API team. They have escalated the question internally to determine whether parent-level activity might be supported in the future.