Want to Get More Out of Your Subject Lines? Try Testing.

How many emails are in your inbox right now? Do you plan to read all of them? If you are like most of us, you probably don’t have that kind of time. Instead you will quickly scan through the list and open the handful that catch your eye. Catching the consumer’s eye is the goal of every marketer, and when it comes to email the subject line is the best way to do this.

Considering how important the subject line is, how often do you test them? Surprisingly only about a quarter of those we surveyed frequently test their subject lines.

How Often Do You Test Your Subject Lines?


That’s like leaving money on the table. Let’s say you send a new promotional email to 1 million subscribers, and you manage to improve your read rate by just 0.1% through better subject lines. That’s 1,000 more people reading your email than before. Wouldn’t that be nice to point to in your next meeting?

The solution
You can have the best content in the world, but if you don’t have a great subject line no one will ever see it. At Return Path we think that would be a shame. So we created the Subject Line Optimizer app as part of our Labs initiative. The goal of the app is to make researching and testing your subject lines easier and faster than ever before.

Instead of doing a poll in the office to see which subject line people like best or throwing darts at a list, you can compare your ideas to the actual subject lines sent by 3,000 top brands. You can view how those subject lines actually influenced read rate, and find inspiration on how to best connect with your audience. See what your competitors and the industry leaders are saying. You can even limit the results to emails from your industry, since what works well for an online dating site may not work well for a bank.

How it works
Enter a subject line you think would be good, or even just one or two important keywords you want to feature in the subject line. Select who you want to be compared to (everyone, or one specific industry), then hit the “Compare” button and watch the magic happen.

As an example, a search for “Mother’s Day Sale” produces the following results across all industries:


What does that mean?
Apparently being excited about wishing people a Happy Mother’s Day is more important than mentioning a sale. You’ll see this at the end of the results where the worst performing subject lines are displayed, along with their performance compared to the average read rate:


The takeaway
Does this mean you should always add exclamation points or never mention a sale? Not at all, but in this particular case the evidence suggests enthusiasm about the holiday is more important and stands out from the crowd than another email about a sale. Every situation and email is different, and what worked for you last month or last year may no longer have the impact you are used to. Keep testing and checking new ideas all of the time.

Where to begin?
The subject line optimizer is a great tool, but you still need to know where to start. What is the right style and tone of subject line for your email? What keywords should you search? Not to worry, we did the heavy lifting for you with our new study, The Art and Science of Effective Subject Lines. Take a look at these surprising results and discover if the “Easter Platypus” approach is right for you. Oh, and in case you were wondering, click-bait subject lines do not work as well as you might think.

What’s next?
Once you’ve done everything you can to become a subject line hero at your company, I would encourage you to also take a look at the subject line’s best friend: the pre-header. This is the text that appears on your mobile phone under the subject line as you scroll through your email app, and is another great way to catch your subscriber’s eye.

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