What is email a/b testing?

Email A/B testing, also known as split testing, is a common practice where you compare two versions of an email to see which one performs better. You send one version (A) to a portion of your audience and another version (B) to a different, similar portion. By looking at the results, like open rates or click-through rates, you can learn what your subscribers respond to most.

This method helps you make data-driven decisions about your email campaigns instead of just guessing. It's about understanding your audience better and continually improving your communication to get better results, whether that's more sales, more website visits, or more engagement.

Why email A/B testing is important

A/B testing is crucial because it takes the guesswork out of email marketing. Instead of assuming what your audience prefers, you can test different elements and see real data. This leads to more effective campaigns, better engagement, and ultimately, a stronger return on your email marketing efforts.

Optimize for better engagement

By testing elements like subject lines or preview text, you can find out what encourages more people to open your emails. A higher open rate means more people are seeing your message, which is the first step toward achieving your campaign goals.

Improve conversion rates

Beyond opens, A/B testing helps optimize for actions. Testing different calls to action (CTAs), button colors, or email layouts can reveal what makes subscribers click through to your website or complete a purchase. This direct impact on conversions is a major benefit for marketing teams focused on sales or lead generation.

Understand your audience better

Each test provides insights into your audience's preferences and behaviors. Over time, these learnings build a clearer picture of what resonates with them, helping you tailor all your future marketing efforts more effectively.

How to set up an effective A/B test

Setting up a successful A/B test involves careful planning and execution. The key is to test one variable at a time to clearly understand what caused any change in performance.

Choose one variable to test

Decide what single element you want to compare. This could be:

• Subject lines (e.g., promotional vs. benefit-driven)
• Sender name (e.g., personal name vs. company name)
• Email content (e.g., short vs. long copy, different images)
• Call to action (e.g., button text, color, placement)
• Layout and design (e.g., single column vs. two columns)
• Send time or day

By focusing on one change, you can confidently say that any difference in results is due to that specific element.

Determine your audience segments and sample size

Divide your email list into at least two similar segments. Each segment should be large enough to provide statistically significant results. Many email marketing platforms will help you with this, often suggesting a sample size of 10-20% of your total audience for each variant, leaving the rest for the winning version.

Define your success metrics

Before you start, know what you're trying to achieve. Are you looking for a higher open rate, click-through rate, conversion rate, or perhaps a lower unsubscribe rate? Clearly defining your goal helps you interpret the results accurately.

Best practices for A/B testing

To get the most out of your A/B tests, follow these best practices:

• Test regularly: Make A/B testing an ongoing part of your email strategy, not a one-time event.
• Be patient: Allow enough time for your test to run and collect sufficient data. This might be a few hours or a few days, depending on your audience size and sending frequency.
• Analyze results carefully: Don't just look at the raw numbers. Use statistical significance tools (often built into email platforms) to ensure the difference in performance isn't just due to chance.
• Document your learnings: Keep a record of what you tested, the results, and what you learned. This knowledge base will be invaluable for future campaigns.
• Iterate and improve: The winning variant in one test becomes the baseline for your next test. Continuously build on your successes.

Email A/B testing is a powerful tool that helps marketers refine their strategies and achieve better results. By systematically testing different elements, you can create more engaging and effective emails that resonate deeply with your audience. Start small, test one thing at a time, and let the data guide your decisions for continuous improvement.