Email Marketing Split Testing: What it is and How You Can Use It to Boost Conversions

Carl Taylor | January 13, 2020

How do you know if your email campaigns are as effective as they can be? Split testing may hold the key to finding out how you can optimise your emails.


So you’ve created an email campaign and it’s doing pretty well.

The open rates are solid and you’re getting some conversions. However, there’s a nagging question in the back of your mind…

“Could my campaign do better?”

You don’t want to scrap a campaign that’s already working. But at the same time, you don’t want to miss out on getting more conversions.

That’s where split testing comes in.

With split testing, you can refine and optimise your campaigns until they achieve peak performance.

And best of all, good split testing will give you the jump on many of your competitors. A shocking 39% of businesses conduct no testing on their email campaigns. That means they have no idea if their campaigns are truly effective or not.

With split testing, you’re no longer part of that bottom 39%.

What Is Email Marketing Split Testing?


Email split testing is a pretty simple concept.

It involves taking an email you’ve created and making a clone of it. You then change a single element of that clone. For example, you may use a different subject line, or rearrange the imagery used in the email.

Then you run both of those emails in side-by-side campaigns. Once the campaigns end, you analyse the results to see which email performed better.

You then update the email with the element that came out on top. And if you want, you can run another split test to examine another element.

Over time, repeated split testing allows you to refine your email so that every element gets optimised.

Why You Should Split Test – The Benefits


After reading the previous section, you may think that split testing seems a little time-consuming. It involves running multiple campaigns, often several times per email, to create an optimised campaign.

We admit that there is a time commitment involved. Furthermore, you have to invest in several short campaigns to split test effectively.

However, the benefits that come from the process far outweigh these downsides.

This is what split testing can do for your campaign:

  • The constant testing of email elements allows you to figure out – and prove – what’s most effective with your audience. This means you eventually create a campaign that maximises the returns on your investment. And once you’ve got the campaign right, you don’t have to worry about testing it again.
  • Many of the results of your split tests will carry over into similar campaigns. For example, you may run several sales campaigns for different products. It’s likely that what works in one sales email will work in all of the others. So you’re optimising more than the campaign you’re testing.
  • Split testing can also reveal when certain email elements aren’t working. For example, you may change one of the colours you use, only to find that your audience response lowers. You now know never to use that colour in any of your email campaigns. And again, this information may carry over into your other marketing campaigns.
  • You’re able to adjust your communications to meet the expectations of your subscribers. The metrics will show you what your subscribers respond to and what turns them away. Give them more of the former and less of the latter to improve engagement.
  • You don’t need anything other than your existing email platform and subscriber list to conduct the tests. This considerably lowers the initial costs of the testing.

Ultimately, split testing saves you money and improves the ROI of your email campaigns. And if you’re a member of the Automation Agency Concierge Service, you don’t even need to conduct the tests yourself. We can help you today if you send us a task.

But let’s assume you want to run the campaign yourself. How do you create a split test that provides you with actionable insights?

Here are the six best practices you need to follow…

Best Practice #1 – Choose a Single Element


Trying to test multiple elements is the key mistake many people make when they start split testing.

Your goal here is to figure out how a single change affects an email campaign. If you make several changes, you can’t nail down the exact effect of each change.

This will prove especially frustrating if your test reveals that your new email gets better results. Your inability to identify the specific element that led to the improvement means you can’t replicate those results in another campaign.

So, always focus on a single element when running your test. Common split testing elements include:

  • The email’s subject line
  • Your initial greeting
  • The CTA, which may be
    • The specific offer made
    • Where you place the CTA
    • The language used
  • Incorporating a testimonial vs. not using one
  • The colours used in the design

There are many more besides.

It’s always better to run multiple split tests that each examine a different element, than it is to run one test that examines several elements.

Best Practice #2 – Create a Hypothesis


This is where you define the goal behind the campaign. Your hypothesis details the change you’re going to make and what you hope to achieve with that change.

For example, a good hypothesis may be the following:

We believe that adding a power word into the email’s subject line will cause more people to notice the email. This will lead to higher open rates.


We think that personalising the email’s opening statement will lead to higher engagement. This will result in prospects reading the full email and clicking through to the offer.

Essentially, you’re defining the result you expect to see. That means you can bring a focused approach to the analysis period of the split test. To see if the change made any difference, you can jump straight to the metrics you hoped to affect.

Best Practice #3 – Don’t Forget the Other Metrics


Your hypothesis will typically focus on affecting a key metric, such as open rates or click-through rates.

But that doesn’t mean the selected metric is the only one you should test. You also need to check that the email doesn’t have a negative effect on other metrics.

For example, let’s say you’re testing a different subject line. It’s a little more clickbaity than your previous one, and makes a specific promise to the reader.

However, you don’t deliver on that promise with the email copy. In fact, the copy seems to have almost no relation to the subject line.

With this test, you’re likely to see an increase in email open rates. That may lead you to believe the change is a success. But don’t be fooled – you’ll probably find that your click-through rate has dropped dramatically, too. That often happens when your email doesn’t fulfil the promise made in the subject line.

So, what seems like a positive result at first may actually have a negative effect on another important metric. And more worryingly, it’s the latter metric that has the largest impact on your ROI.

The point is that you have to look beyond the specific metric you’re testing. Changing an element of an email may have more wide-reaching effects than you anticipated in your hypothesis.

Best Practice #4 – Extend Split Testing Beyond Your Emails


You know that your email campaigns are only part of a larger marketing campaign. Typically, you’ll run ads to pull people towards a landing page. Those people subscribe to your list to gain access to a lead magnet. That means you’re now able to send emails to them.

The point here is that split testing needs to go beyond your emails. You also need to test your ads and your landing pages to ensure they’re as effective as possible. Furthermore, these tests may hold clues as to why an email campaign struggles.

For example, you may find that changing an element on a landing page makes it more consistent with your email campaign. This, in turn, can lead to higher click-through rates for your emails, because your message stays consistent.

Thus, a split test in one area affects the results you get from others.

Automation Agency can help you to set up split tests for both your emails and landing pages. Just send a task to the Concierge Service to get started.

Best Practice #5 – Set Audience Limits


It’s generally considered poor practice to run a split test on your entire subscriber list.

There are good reasons for this. You have to think about what will happen if the changed element leads to the campaign failing. If you’ve sent it out to your whole list, that failure occurs over a much larger audience. Meaning you’ve spent a lot more money to find out that something doesn’t work. And not only that… if the failure was bad enough, you might have succeeded in annoying your entire subscriber list.

Set a limit on the size of the audience you’ll test the emails with. Once you have the result, you can then roll out the optimised email to your full list.

Best Practice #6 – Keep All External Elements Consistent


There are several external elements that affect the success of an email campaign, beyond the content.

For example, the time of day you send the email can have a large effect. You may find that more people open emails during the morning than they do in the afternoon.

It’s important to maintain consistency across these external elements when running your test. Otherwise, you may find that something other than the changed element affects the results.

Create Your Split Test Today


Effective split testing allows you to identify what your audience expects from your email campaigns. With testing, you’ll optimise the copy you send out and achieve a larger return on your campaign investments.

However, it’s crucial that you stick to the practices defined above to get accurate results. A skewed test could lead to you making permanent changes that damage your campaign.

Automation Agency is here to help you run accurate split tests that follow industry best practices. Just send a task to the Concierge Service to get started.

But what if you’re not a member yet?

If that’s the case, you might want to find out if we’re a good fit for your business. Start a conversation with our Right Fit Bot to learn more about us and what we do.

About the author 

Carl Taylor

Carl Taylor is the Founder & CEO of Automation Agency. For the past 10 years Carl has been building businesses and marketing them online through the use of Sales Funnels, Email Marketing Automation, Landing Pages, and Wordpress Websites. Carl is also a #1 author and highly sought after speaker and consultant whose work has impacted thousands of businesses across various industries worldwide.

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