Testing email subject lines to see which works best

You only have one tool at your disposal to persuade people to open your email marketing messages. It’s your subject line, and it has to work bloody hard considering it’s only a few words long.

How do you identify the best-performing email subject lines?

Easy. Test a few different approaches and see.

If you want empirically sound test results, you need to mail your campaign to a large number of people otherwise the conclusions you draw will be statistically meaningless. If two out of a hundred prospects open your email, you can’t conclude anything sensible from it. But if you mail out 5,000 and 50 people open it, your conclusions are much more reliable.

Tiny, weeny database?

What can you do if your prospect or customer database is really small, containing fewer than 500 people? Try using the same subject line a few times in a row, then change it. It’s slow and laborious but at least it’s sensible.

Massive database?

What if you have a massive database containing thousands of names? If you split-test various subject lines using a different one for each segment of 2000, 5000, 10,000 or whatever, you’ll identify the best performers much sooner. Whatever you do, make sure your email marketing system tells you how many people opened your email. If you don’t know, you’ll be perpetually in the dark.

I’ve been trying to get more prospects to open a client’s weekly email marketing messages for a while now. So far, the best-performing subject line included the phrase Who ate all the pies? Which just goes to show, you never know what’s going to ding people’s bell until you suck it and see!

(Thanks to sxc.hu for the fab free image)