The best cold emails are discovered, not guessed. A/B testing is how you find what works.
What to Test (In Priority Order)
- Subject Lines: Biggest impact on opens. Test first.
- Opening Lines: First sentence determines if they keep reading.
- Value Propositions: Which benefits resonate most.
- CTAs: What action are they willing to take.
- Length: Shorter vs longer.
- Timing: Send day and time.
How to Test
Sample Size: Minimum 100 sends per variant, ideally 200+.
One Variable: Only test one thing at a time.
Control Group: Always keep a baseline to compare against.
Statistical Significance: Don't declare winners too early. Use a significance calculator.
Subject Line Testing
Test types: Question vs statement, personalization vs generic, length, curiosity vs clarity, specific vs vague.
Example test: "Quick question about {{company}}" vs "{{firstName}}, thoughts on [topic]?"
Opening Line Testing
Test: Personalized observation vs generic hook, question vs statement, compliment vs challenge.
CTA Testing
Test: Meeting request vs content offer, specific time vs general availability, direct vs soft ask.
Interpreting Results
Statistically significant: 95% confidence the difference is real.
Practically significant: Is the difference worth acting on?
Document everything: Build a knowledge base of what works for your audience.
Continuous Testing
Never stop testing. Markets change. What worked yesterday may not work tomorrow.