Your subject line is possibly the most influential factor in engaging your audience with email marketing. Those few words can make or break a campaign. It’s what your recipient scans in their inbox and helps them make a split second decision whether or not to open the email or hit delete.
You might spend hours crafting what you think will be the best subject line for your email campaign (or you might spend 5 seconds!), but how do you know if it is the best subject line? Well! If you split test your email subject lines, this can give you some extremely valuable insights as well as massively improve your email open rates.
Note: most email marketing software offer an A/B test feature. The set up and options available with each provider will differ, so please refer to their help/support for more information.
What is A/B (or split) testing?
Usually this involves splitting your email database into two and writing two different subject lines. You would then send half your database the email with subject line 1 and the other half the email with subject line 2. You would then wait a set amount of time and review the results in terms of open rates. The one with the highest open rate could be seen as the best subject line that was better than the other at encouraging recipients to open the email.
This would be a very basic way of testing two subject lines. The problem with this approach is that half your database get a substandard email.
If we want to go a step further and refine this process, we can split test 2 subject lines to a small portion of our database. Review the results. Then send the winning email to the remainder of the database. This way, the majority of your database will receive the best version of your email. So, we are not only conducting our test, we are also using the results to gain a better open rate for the campaign overall.
What to split test
It’s not just about what you say in the subject line, but it’s also about how you say it. You’ll want to consider the following when testing different subject lines:
- personalisation – adding in data from your list vs. a generic subject line: “This email’s for you, Heather” vs. “This email’s for you”
- asking a question vs. a simple statement: “Have you seen our latest product?” vs. “Here’s our new product”
- length of the subject line – can you try being more succinct vs. more descriptive? “New product announcement!” vs. “Here’s a overview of our new product to help you achieve your goals in business and we think you will love it. Find out more in this week’s email!”
- creating intrigue/mystery (i.e. not giving everything away in the subject): “If you buy one product this year, this should be top of your list” vs. “If you buy one product this year, the XYZ widget should be top of your list”
- spam trigger words – open rates can be improved if we avoid the spam filters, so if you’re using spam trigger words, try subject lines without them. For a full list of spam trigger words, see Hubspot’s list here.
Judging the winner
Focussing on the subject line and your open rates can pose an issue. We lose focus on the bigger picture and forget that our email campaigns are all about engaging with our audience and encouraging them to visit our website, read our blog or buy something from us.
It’s tempting to go down the clickbait route just to increase open rates. However, this is likely to annoy recipients who open your emails only to find that the content doesn’t meet their expectations.
This will negatively affect your click rates and conversion rates, so it’s important to judge your A/B tests on not just your open rate. For a subject line to be deemed a winner, it must improve open rates whilst also improving click rates (or at the very least, not negatively impact your click rate).
Ready to split test your email subject lines like a pro?
One final thing to consider before you split test your email subject lines is the size of your database. If you only have a few hundred people on your list, the sample size you use for each version of your subject line will be too small to determine a winner and you may find you get inconsistent results, so we’d recommend only conducting test on larger databases.
If you have a large database that you’re emailing regularly and feel you’ve hit a bit of a plateau in terms of engagement on your email campaigns, running A/B tests is a great way to spice things up a bit and inject some creativity (backed up with data) into your campaigns to get better results.
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