Cold email outreach A/B testing framework

Build a systematic cold email testing program. Setup: 1. Define hypothesis (subject line, CTA, length). 2. Split list into equal segments (minimum 100 contacts each). 3. Send variant A to segment 1, variant B to segment 2. 4. Wait 3-5 days for statistical significance. 5. Measure open rate, reply rate, meeting booked rate. 6. Calculate winner (minimum 95% confidence). 7. Roll out winner to remaining list. Variables to test: personalization depth, value proposition clarity, email length (50 vs 150 words), CTA placement. Use Lemlist or Woodpecker for tracking. Document learnings in playbook.