Best Practices for Email A/B Testing to Boost Your Campaigns

When sending emails to your subscribers, do you ever wonder which version would get more clicks or convert better? If so, you're already thinking about A/B testing, a method top marketers use to optimise emails. By testing one variable at a time, you can determine what resonates best with your audience and make data-driven improvements to your email marketing strategies.

What is A/B Testing in Email Marketing?

A/B testing, or split testing, involves sending two variations of the same email to two segments of your email list. The goal is to see which version performs better based on a specific metric, like click-through, open, or conversion rates. By isolating one variable per test, you can pinpoint the factor driving the success or failure of your email marketing campaigns.

Start Small: Test One Variable at a Time

It might be tempting to tweak multiple parts of your email simultaneously, but A/B testing is most effective when you change just one element. Whether it’s the subject line, CTA buttons, or preview text, focus on testing one variable per experiment. If you change too many, you won’t know which factors impact your performance.

For example, you could test your email subject line first. Does a question-based subject line get more open than a straightforward one? Once you know, you can apply that insight to future emails.

Before you start A/B testing, make sure your email list is large enough. A small sample size may not provide meaningful results. Tools like Campaign Monitor can help calculate the correct sample size based on your audience.

What to Test in Your Emails

While every business is different, certain variables are consistently worth testing across campaigns:

• A great subject line often differs between an email getting opened or ignored.
• Your call-to-action placement, colour, and wording can significantly impact click-through rates.
• Preview text snippets seen after the subject line can encourage or discourage opens.
• Test whether images or text-only emails perform better.
• The Day and time of email sending can affect engagement levels.

Even something as simple as testing whether including a person's name in the subject line increases open rates can offer insights that reshape your strategy.

Email Subject Line Testing: A Powerful Starting Point

Your subject line is often the first and only thing your recipient sees before deciding to open your email. With attention spans shrinking, crafting a subject line that captures interest is critical.

For example, test whether including a question in your subject line increases clicks. Something like “Need a business tip today?” may outperform “Business Newsletter #23.” Tools like Mailchimp make it easy to set up subject line A/B tests and track the results.

 How to Set Up an A/B Test

Setting up A/B tests can be simple, especially with platforms like Litmus, Campaign Monitor, or Mailchimp that offer built-in testing features. Here’s a quick step-by-step guide:

1. Define Your Goal: Are you trying to improve open, click-through, or conversion rates?

2. Choose Your Variable: Decide which variable you want to test (e.g., subject line, CTA button).

3. Select Your Sample Size: Make sure it’s large enough to provide statistically significant results.

4. Create Your Variations: Draft two versions of your email, changing only the element you’re testing.

5. Send and Wait: Send the emails to your test groups and allow enough time for recipients to interact with them before analysing results.

6. Analyse the Results: Use the data to choose the winning version and implement that change across your campaigns.

When to Test the Day and Time 

While many focus on content elements like subject lines and CTAs, the timing of your email is another critical factor. For example, if you send your emails on Tuesday mornings, test whether sending them on Thursday afternoons results in higher engagement.

You might be surprised that the Day of the week or even the time of Day can drastically affect performance. Try sending the same email at different times and compare click-through rates. Platforms like Campaign Monitor provide detailed analytics, allowing you to track how timing influences performance.

Click-Through Rates vs Conversion Rates

It’s easy to get wrapped up in open rates, but don’t forget to track click-through and conversion rates. Open rates tell you how well your subject line performed, but clicks show how engaging your content is. Conversion rates, meanwhile, tell you whether your CTA is doing its job.

Use tools like Litmus to track the performance of multiple metrics, like how your emails look across different devices and whether your content is loading correctly. These details can influence testing results and help optimise emails for better performance.

What Happens Next?

Once you’ve gathered enough data from your tests, it’s time to apply those findings. Implement the changes that resulted in higher engagement and continuously test other variables. A/B testing isn’t a one-time thing; it’s a long-term strategy to refine your approach.

If your audience responds better to personalised subject lines, use this strategy. If you find that blue CTA buttons convert better than red ones, apply that insight across all campaigns. Remember, the goal is continuously improving by making small, data-backed changes.

Building an Ongoing Testing Strategy

The beauty of A/B testing is that it doesn’t stop after one experiment. Successful businesses keep testing new variables to optimise emails and stay ahead of their competition. To maintain momentum, consider setting up a quarterly testing calendar. This will keep you accountable and ensure you’re regularly improving your email marketing strategies. A platform like Mailchimp offers robust reporting and testing features, allowing you to compare campaigns over time.

A/B Testing for Long-Term Success

Email marketing can be a robust sales for UK small business owners and entrepreneurs. A/B testing takes the guesswork out of the process and lets you optimise emails based on actual data. Whether you’re testing subject lines, CTA buttons, or timing, these small changes can add to significant improvements that significantly improve click-throughs like Litmus, Mailchimp, or Campaign Monitor. You can quickly start A/B testing today, knowing that each test brings you one step closer to a more effective email marketing strategy. By staying committed to testing, analysing, and applying insights, you’ll see steady improvements that help your business thrive through email marketing.