Space CRM / Blog
A/B Testing Email Campaigns: What to Test and What Moves the Needle
A/B testing framework for email marketers — subject lines, send times, CTAs, and content — with real data on what works.
What to test first
Subject lines have the biggest impact on open rates. Compare: question vs statement, short vs long, personalized vs generic.
After subject lines, test send time, then CTA button text, then email length. Test one variable at a time.
Statistical significance matters
Never call a winner before reaching 95% statistical significance. With a list under 1,000 contacts, most A/B tests are statistically meaningless.
Run one test at a time. Testing subject line AND send time simultaneously makes it impossible to know which variable caused the difference.
Building a testing culture
Document every test: hypothesis, result, sample size, and conclusion. Build a swipe file of winning subject lines and CTAs.
Use SpaceCRM's built-in A/B testing to automate split sending and auto-deploy the winner to the remaining list after a set time period.
