Skip to main content

Scenario

You’re about to send a campaign and you have 10 candidate subject lines. Instead of guessing, you pull historical campaign data (subject lines paired with open rates), then run a Focus Group where synthetic personas rate each new subject line on a 1–10 likelihood-to-open scale. The result is a ranked list of subject lines with qualitative explanations before you hit send.

Architecture

Code

Example Output

Error Handling

The prediction quality depends on having 15+ historical campaigns with diverse subject line styles. If your history is limited, the Focus Group still works but has less context for calibration.
For open rate prediction, use personas that match your actual subscriber demographics. The sample personas (Mobile Scanner, Power Reader, etc.) are archetypes — replace with personas from Job 1 for better accuracy.
Testing 10 subject lines in one question is the practical maximum. For more candidates, split into multiple Focus Groups of 10 each, or use a preliminary round to narrow to 5 finalists.

What’s Next

Mailchimp Integration

Back to Mailchimp integration overview

Re-Engagement Builder

Win back dormant subscribers

Focus Groups API

Full reference for POST /api/v1/focus-groups

All Integrations

50+ API integrations with full code