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:
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The parent campaign is never actually sent to recipients.
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Only the child campaigns have delivery and engagement.
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Mailchimp does not aggregate open/click activity back into the parent.
How does MC4SF handle this?
In releases after version 1.185, MC4SF resolves this automatically using Mailchimp’s sub-reports. During the campaign sync we discover the Winner and Combo variants of each A/B or multivariate campaign, create them as child campaign records linked to the parent, and store per-recipient email activity (opens, clicks, bounces) against those child campaigns.
On the Campaign Detail modal, a Variant picklist lets you switch between Winner and Combo variants on both the Members tab and Email Preview, so you can see exactly who received each variant and what it looked like.
This behavior is controlled by the Sync Variate Children setting, which is on by default. Support may turn it off for an org if a catch-up sync would exceed storage or callout limits.
What about older versions?
On versions 1.185 and earlier, email activity for A/B and multivariate campaigns is not synced, because the parent campaign has no activity of its own and the child campaigns were not discovered. Upgrade to the latest release to enable variant activity sync.
