5 ideas for subject line testing

I’ve been speaking with a lot of my clients lately about their email plans. To my great pleasure, most of them are striving to do more A/B split testing on their emails, specifically subject line testing, to see what resonates most with their subscribers.

For most of these clients, they know what their goal is: to see what type of subject line generates the most email opens. (Note: Some also have higher click-throughs or conversions as their goal). That much they know.  I’ve found a common trend though: they don’t know what to test in their subject lines in order to reach this goal.

With this in mind, here are five great subject line tests that are worth trying.

1. Specific versus General

One of my adult education clients sends emails to prospective students about upcoming open house events.  Historically, their subject line was something like “Attend our Open House on November 12”.  Direct and to the point, right?  One day, we decided to try a more general subject line, “A Foundation for Success”.  And much to our surprise, the less-specific subject line garnered more email opens!  We’ve tested it several times since then, and the general subject line always wins.  Apparently these subscribers like the element of surprise in their inbox!  Try this for yourself – one subject line with a specific call-to-action and another with a more general teaser line.  The results may surprise you!

2. Personalization

We’ve all seen the “Joanna, get 10% off today!” type subject lines.  The first name personalized subject lines have been around forever, and they seem to have lost their impact.  But why not try other personalization tactics?  Try adding the subscriber’s location or other demo/geographic information to the subject line.  Seeing something personal about themselves might make your subscribers want to open your email and read more.  Here’s a great example: on a recent gloomy day in Charlotte, North Carolina, my colleague received an email from Qdoba offering a rainy day special.  The subject line was “Rainy Day Special from Qdoba Mexican Grill”.  You can’t get much more personalized than that!  Take a look at your subscriber database.  What information do you have on your subscribers that you could use in your subject lines?

3. Company/Branding

Another great test to try is adding your company or brand name to the subject line.  Of course, your company or brand name will show in the From Name, but will adding it to the subject line as well increase your open rate?  In many instances it will, as subscribers will recognize the email more as coming from a trusted source.  One of my online retailer clients (let’s call them Acme) recently sent an email with the subject line “Save 15% on spooky Halloween cards & invites!”  Could adding the company name to the subject line, like “Save 15% on spooky Acme Halloween cards & invites!” or “Save 15% on spooky Halloween cards & invites from Acme!”, have increased their response rates?  You never know until you try!

4. Negative versus Positive

Have you noticed that many subject lines are so negative?  For example, consider this subject line I just received, “Enterprise Marketers: Social Media Management Woes?”  While it’s direct and intriguing, it is assuming that we all have woes at work, which is depressing.  While this type of subject line may work for some, why not try a more positive spin?  For example, “Enterprise Marketers: Improve your Social Media Management”.  Again, it’s direct and intriguing, but is uplifting and promises good things!  See what works for your subscribers by testing a positive subject line against a negative one.  It might give you some good insight regarding the general moods of your subscribers too!  (Side note: I wonder if a negative subject line would work better on a Monday morning when we’re all grumpy and want to commiserate versus a Friday afternoon when we are in a more positive, happy mood … something to test!)

5. Urgency

This one is my favorite.  Will adding a due date or expiration date to your subject line make your subscribers open your email more?  This is a great one to test during the holidays, since we are all on tight present-buying deadlines.  Try adding the ship-by date to your subject line, like “Only 5 more days to get guaranteed shipping by Christmas!” and compare it against a date-less one, like “Get guaranteed shipping by Christmas!”.  Or try testing a sale announcement with and without a date limit, like “5 days only – Get 15% off!” versus “Get 15% off!”.  Don’t have an expiration or due date to use?  Make one up to create urgency!  (Just don’t do this too often or you’ll become the boy who cried wolf.)  Brainstorm with your team to come up with ways to make your subscribers feel like they need to open and take action on your email today, or else they’ll miss out!

Final Thoughts Before You’re Set Loose

Remember, the key to email subject line testing is having a control group. It’s imperative to have this so you can get accurate results on the winning subject line.  So, for example, if you want to test branding within the subject line, make sure you have an exact replica without the branding, like this:

  • Control: Enjoy 10% off your next purchase
  • Experimental: Enjoy 10% off your next Acme purchase

You can also test more than two subject lines at once, but remember to only change one variable at a time.  This will help you to understand what caused the winning subject line to perform the best.  Note: you can do this type of more advanced testing using Publicaster’s A/B split tool.

For example, if you want to test branding and urgency at the same time, try this format:

  • Control: Enjoy 10% off your next purchase
  • Experimental 1 (branding): Enjoy 10% off your next Acme purchase
  • Experimental 2 (urgency): Only 3 days left to enjoy 10% off your next purchase
  • Experimental 3 (branding & urgency): Only 3 days left to enjoy 10% off your next Acme purchase

And finally, before you start testing (and this goes for testing anything in your email program), decide what your goals are and what will determine the “winner”.  Most often with subject line testing, your winning version will be the one that generated the highest open rate.  But if you’re testing a different offer, your winner could be the offer that garnered the highest click-through or conversion rate.  Be sure you’ve decided this beforehand as well as what margin of error you will allow before deciding on a winner.

So there you have it, you no longer have an excuse as to why you aren’t doing subject line testing!  Start with these five simple tests, and you’ll be well on your way to finding the best subject line for your subscribers.  If you’re a WhatCounts client and need help with some more A/B split test ideas, contact your client services manager today.  Not a WhatCounts client yet?  Get more info today, we’d love to have you!

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2 Responses to "5 ideas for subject line testing"
  1. Shelley K. says:

    Joanna or Christopher, could you provide examples of subject lines that nonprofits could test? We’re not selling anything and can’t offer discounts. We need more members to open our emails, which focus on legislative issues. Thanks.

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