Compare subject lines in an A/B test

The email subject line is the first element of your email message that your target audience sees. You can conduct an A/B test to determine the best email subject line.

You can create several email documents, each with a different email subject line, and add each document to a separate test split in an A/B test. You might instead create a single email document in the Message Editor that contains multiple email subject lines. In the A/B test, select each version of the subject line as multi-content in separate test splits. Do not conditionalize the multiple subject lines with personalization rules.

In the A/B test, to find the most appealing variation of the subject line, select Maximum unique views as the evaluation criteria. The objective of the test is to determine which subject line variation compels the greatest number of recipients to open the email.

You can also use the A/B test to find the subject line variations to avoid. Select Minimum unique complaints as the evaluation criteria. The objective of the test is to determine the email subject line least likely to compel email recipients to mark the email as spam.

The scenarios described here require conducting separate A/B tests. You can select only one evaluation criterion for each A/B test.