How A/B testing can improve your email marketing campaigns

How A/B testing can improve your email marketing campaigns

A/B testing, or split testing, is a technique used by digital marketers that allows you to compare different versions of the same content, whether it’s a web page, landing page or email campaign. The goal of A/B testing is to determine which version performs better with users, analysing their engagement and interactions with the content.

In email marketing, the performance of campaigns is critical to determining their success. We rely on specific metrics to gauge whether or not an email campaign can be viewed as successful, with the most common being open and click rates. When creating email campaigns, there are many factors that can impact their effectiveness. Ensuring the recipients are relevant, sending at suitable times, using strong subject lines, and having high quality content are all factors that influence the likelihood of a goal being reached. Therefore many aspects of an email campaign need to be on the mark, which is why A/B testing in email marketing is so vital.


Types of testing

Testing campaigns is a major part of email marketing. Once an email has been sent, any errors can’t be changed and recipients will receive that version. Because of this, sending test versions of emails to yourself and other members of your team is highly important. It allows for all links to be checked and any grammatical errors to be identified and corrected. 

A/B testing on the other hand isn’t used as a way of checking the functionality and readability of the content, but instead to determine the effectiveness. Each version of the email may vary in degreeing amounts, for example the content may be identical but with different subject lines, or each version could use completely different templates and designs. A/B tests commonly use two smaller subset lists taken from a portion of the full email list, which will both contain the same number of contacts. 

Both are sent at the same time, and the results from each will determine which version is more effective. This then allows you to select that version to be sent to the rest of the email list, giving the greatest chance of success. Another useful benefit of A/B testing is that it allows for both HTML and plain text versions of the same email, as the formatting can be a crucial factor in email marketing with spam filters becoming stricter.


Levelling up your campaigns

Small changes can yield big results in email marketing. It may be something simple like the positioning of a CTA or the first line of text that recipients will read. A/B gives you the best chance at identifying the features that work before sending to the main portion of contacts. When designing an email and spending significant time on it, tunnel vision begins to set in and it becomes difficult to identify what could be improved. Therefore A/B testing essentially acts as a survey to see which versions get the best response.

Good subject lines are vital for strong open rates, as they’re the first part of the email that recipients see. Choosing one can be tricky and a lot of time can be spent going back and forth on ideas, carefully wording them in order to best grasp their attention. For subject line testing, open rates will be the key metric to monitor. Significant differences between the two in the A/B test results will help you choose which one to progress with.

Another great use of A/B testing is to determine the likelihood of spam filters opening the emails. Each campaign will have multiple links, often a CTA, website URL and social media links. Once the email is sent, viewing the click reports will often help to identify whether or not your email is being opened by spam filters rather than actual recipients. The easiest way to identify these is to view the timings of the clicks (i.e. opened instantly after sending), and whether the same recipient has clicked all links within the email.



A/B testing, whether for the content itself or subject lines, gives a quantitative basis on which to make adaptations. For example, an A/B test may result in both versions underperforming, and it becomes a matter of making greater changes to the email campaign in order to better suit the target audience. If it’s a case of emails being flagged as spam, sending A/B tests with HTML and plain text versions may yield favourable results for the plain text versions where spam filters are less likely to flag due to no images. As with any digital marketing channel, testing is a necessary step and will continue to be going forward, as competition continues to grow.


About Inflowing

Inflowing is a B2B marketing agency. We help B2B organisations do meaningful things with marketing. Whether that’s getting more leads, more visibility, or supporting their sales teams.

We’re an experienced team of marketers with an incredibly strong background in B2B. To learn more about B2B and improving your marketing, check out our other blogs or get in touch.

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