A/B test your email.
See what works better.
Try two to six versions of a broadcast and see which one people actually responded to. You can test more than the subject line: the whole email, the address it comes from, even the sending service it goes through.
Bots and security scanners stay out of the results.
Test more than the subject line.
Compare subject lines, whole emails, the address it comes from, or the sending service it goes out through. Change one thing or several at once.
The sender and sending service are worth testing too. A test can show whether people open more when an email comes from a person's name than from your company's, or whether one sending service gets better results with your list than another.
Don't let machines distort the result.
Security scanners click links before a person ever sees the email. If those clicks count, the version with more scanner traffic can look like the better email.
The report shows both: the numbers before and after bot activity is taken out. If filtering changes which version came out ahead, it tells you, so you don't roll out the wrong subject line.