A/B Testing: The Ultimate Litmus Test For Your Email Marketing Campaigns

“Hello Mr. Smith” or “Hi Smith!”

“Buy now” or “Call us for more information”

“Buy 1, Get 1 FREE!” or “Free shipping on orders over $50”

In the above pairs, which salutation, call to action and offer is ‘better’?

If you said, “That depends on many factors”, pat yourself on the back because you’re absolutely right! When it comes to email campaigns, the right answer to a question like the one above will rarely just magically appear at the start of the campaign. The best salutation, the most effective CTA and the most compelling offer – these are all elements (and they’re not the only ones!) that require thought, experimentation and lots of patience. When you get these elements right, your email’s click-through and open rates can increase which can result in more conversions and voila – more sales!

And what is the best way to ensure that you get these elements right?

A/B testing!

A/B testing is literally the ‘litmus test’ your email campaign needs to pass in order to successfully meet its goal, whether it is to connect with new customers, to engage with and retain existing customers, to enhance your brand’s equity, or some combination of all these.

What is A/B testing: The Basics

In an A/B test, you set up different versions of an email campaign and send each to a different group of recipients. These groups comprise a small percentage of your larger group of subscribers. The version that generates the best results is determined to be the ‘winning’ version which is then sent to the remaining subscribers.

A/B testing – also known as ‘split testing’ – helps you determine which email among multiple versions is likely to get more opens, clicks and conversions. Equally important, it is a great way to determine which email is likely to fail. And why would you want to waste time sending emails that don’t work?!

What Can You Test In A/B Testing: The Elements

In an A/B test, you can test almost anything! In fact, if your campaign is critical to your marketing or organizational goals, you should test more than one element. However, to get accurate results, it’s important to only test one element at a time.

The most commonly-tested elements in A/B testing are:

  1. Subject line

Since your email’s subject line is the first thing your recipients will see, it has a direct effect on open rates. Therefore it’s important to include this element in your A/B testing.

You can test your subject line for:

  • Length
  • Word order
  • Content

Subject lines that contain between 61-70 characters and that ‘front load’ the benefits usually get better open rates. Testing different content pieces in the subject line can help you learn what kind of content resonates with your audience, which will also increase open rates. You can also play with emojis and personalization, and test their effects on your test audience.

Consider these example subject lines for the same email:


Don’t let your gut instinct decide the best subject line. A/B test!

  1. Content

Over the past few decades, human attention spans have fallen drastically. Therefore, marketers need to be very careful about crafting copy that can capture their audience’s interest quickly and retain it for more than a few seconds.

But how will you know what a ‘great copy’ looks like for your audience? By A/B testing different types of copy!

Depending on your brand and email marketing goals, test for:

  • Length: Minimal or long-form?
  • Tone: Casual or professional? Funny or serious? Motivational or to-the-point?
  • Layout: Single column or two columns, consistent alignment or mix-and-match

You can also test for text placement, colors, fonts and font sizes.

iii. Images/visuals

Remember the old saying, “A picture is worth a thousand words”? It’s true! The human brain processes visuals much faster than text. Get your visuals right and getting your message across will be a piece of cake! An expert html email developer can help you create a flawless responsive email design.

  1. Personalization

Studies have shown that including personalization in emails is one of the most powerful ways to increase click-through rates.

Here are some effective ways to do this:

  • Address recipients by name in the salutation. “Hello Joe” works much better than “Dear User”
  • Include their name or their company’s name in the body copy
  • If you have extra details about them in your email list, you can even personalize the body copy for increased relevance

Here is a great example of personalization to inspire you for your next email campaign!

email campaign

  1. Call to action

The right call to action (CTA) in terms of copy and design can help increase your click-through rate by making it clear to readers exactly what step they need to take next.

What you can test for:

  • Button versus text link
  • Action type
  • Word placement

Word placement

Common CTA examples:

CTA examples

Other elements you can test in A/B testing

  1. From name
  2. Headline
  3. Links in copy (e.g. social media)
  4. Closing text
  5. Offer
  6. Sending time

The goal of A/B testing is to identify the best design and text-related elements for your email campaign that can transform your audience’s reaction from “Meh! Delete!” to “Wow! This looks amazing!”

How to set up A/B testing: The Process

A/B test requires experimentation but the experiment is more likely to succeed if you follow a robust process that includes the following steps:

following steps

  1. Define a hypothesis

Create a hypothesis about why a particular variation might perform better than the other. Examples:

  • Personalizing the subject line with the subscriber’s first name will increase the chances of it getting opened
  • A CTA button at the top instead of the bottom will increase conversions
  • Most of my readers will open my email on a smartphone so shorter text with images will retain their attention

Once you choose your hypothesis, you will know what to test.

  1. Set up A/B testing

Prioritize the ideas that are most likely to generate the most impact with the least effort. Create the variations.

  1. Choose the recipients

When both versions of the campaign are set up, choose the subscriber lists to send each version to. Also select the size of your test groups (say 20% of your subscriber base), decide how the ‘winner’ will be chosen and set the testing period.

  1. Start the test or schedule for later

Depending on the tool you use, you may be able to either start the A/B test immediately or schedule it to start at some other time of your choice.

Make sure you check for errors before you start the test, because you can’t make changes when it is in progress.

  1. Monitor the results

As the performance metric, you can select open rate, total unique clicks, total clicks on a selected link, revenues earned, etc. Which email variation performs best in terms of the selected metric?

Once the winner is decided, the winning version of the email is sent to all remaining recipients at the same time. If the test results are inconclusive, go back and rework your hypothesis.

Tips and Best Practices to help you Maximize your A/B Testing Success:

Here are a few tips to keep in mind when running an email A/B test for your email campaign:

  • Always start with a goal: Why do you need A/B testing? What do you hope to achieve?
  • For more accurate results, test as large a sample as possible
  • Randomize your contact list and choose the same sample sizes for both versions
  • For best results, test only one variable at a time. To test more than one variable, consider multivariate testing

Wrap up

A/B testing provides a cost-effective and controlled means of understanding which content and visual arrangements are likely to work best with your target audience. It takes the guesswork out of your email marketing efforts and increases your chances of meeting – and even exceeding – your goals. For best results, A/B test and analyze all your email campaigns: marketing emails, transactional emails, thank you emails, etc. Most ESPs have the A/B testing option for your emails integrated right inside their email editors. So, if you have a Mailchimp email template, a Salesforce email template or Pardot email template to A/Btest, things are going to be easy.

A/B testing has delivered amazing results for thousands of email marketers all over the world. If you do it right, there’s no reason why it shouldn’t do the same for you!

Author Bio

Kevin George is Head of Marketing at Email Uplers, one of the fastest growing PSD to Email coding companies, and specializes in crafting professional email templates, custom design and coding in addition to providing email automation, campaign management, and data integration & migration services. He loves gadgets, bikes, jazz and eats and breathes email marketing. He enjoys sharing his insights and thoughts on email marketing best practices on his blog.

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