Testing Email Subject Lines

You can test several subject line variants in two methods:

1. Add alternative subject lines in a single message.
2. Split the contact segment and send separate campaigns.

Method 1. Multiple Subject Lines in One Email

1. Open the message in the editor.
2. Enter the primary subject line in the Subject field.
3. Click + Add subject and enter an alternative subject line.

You can add an unlimited number of alternative subject lines.

When you send the campaign, the system automatically and randomly splits contacts into equal segment based on the number of subject lines.

Evaluating Test Results

1. Go to Campaigns → Reports.
2. Open the report.
3. Open the Experiments tab.

Performance metrics appear for each subject line.

The larger the number of contacts in the campaign, the more accurate the test results.

📘

Note

Google Analytics will collect statistics within one campaign without details by subjects. If you need to determine how many sales a particular subject made, use testing with a segment’s splitting.

Method 2. Testing by Splitting the Segment

Use this method if you need to evaluate not only opens but also conversions or sales for each subject line.

1. Go to Contacts → Segments.
2. Open the segment and click Split segment.

3. Enter the number of parts (maximum — 8).
4. Set the splitting by percentage or by number of contacts.

To create segments with an equal number of contacts, enable the Split evenly toggle.

After you save the changes, the system creates new segments.

Running the Test

1. Create several messages according to the number of segments.
2. Keep the content the same and change only the subject line.
3. Give the messages different names for accurate analysis in Google Analytics.
4. Launch a separate campaign for each segment and select the corresponding message.

You will receive separate statistics for each subject line both in the system and in Google Analytics.