George Foley argues that traditional A/B testing for email open rates is now obsolete thanks to massive datasets. He claims tracking opens damages deliverability and recommends using concise, one-word subject lines based on patterns from millions of emails instead.
Previously, we wanted to track open rates because there wasn't enough good data out there around what gets open and what doesn't. And so we really had to A/B test to see what we're performing. But now people have sent millions of emails. We know roughly what good subject lines look like, and it just hurts our deliverability if we are tracking open rates. So for that reason, we can just utilize one-word subject lines. Getting emails opened in 2025 is nice and easy because we know what subject lines to
