$ man lemlist-wiki/ab-testing

A/B Testing in Sequences

Test subject lines, not entire emails. One variable at a time or the data is useless.

1. Subject lines - Highest leverage. Same email body, different subject. Need 100+ sends per variant for significance.

2. Opening line - Personalized vs generic opener. This is your second-highest leverage point.

3. CTA - Calendar link vs "reply with a time" vs question. Test this after you've optimized open rates.

4. Send time - Morning vs afternoon. Only test this with 200+ sends per variant.

Changing the subject line AND the email body AND the CTA between variants. Now you have no idea what moved the needle. One variable. Always one variable.

Lemlist makes it easy to create variants at each step. Use step-level A/B, not campaign-level duplication.