Email Marketing

Email testing basics to increase your email conversion rate

Learn to determine which messaging will work best for various audience segments

What makes email marketing particularly effective is the ability to create personalized messages that cater to various customer preferences. But how do we know which messaging strategy would resonate most with what audience? With email testing, marketers can easily determine what works best for each audience segment.

Meet the expert
Marie Honme
Marie Honme
VP Strategy

As VP Strategy, Marie provides strategic consultation and insight for Data Axle clients, and has created marketing strategies for various companies including Coca-Cola, HP and U.S. Bank. With over fifteen years of experience in the digital marketing space, she is passionate about developing strategies that deliver a complete brand experience while supporting long-term consumer engagement. Marie has also spearheaded the development of mobile reporting and analysis for the organization by designing new ways to track and measure mobile engagement. In addition, she has co-authored Data Axle's industry-leading benchmark reports resulting from the analysis of over 5 billion emails sent across 20 industries.


What is it?

Email testing is the technique of using a small segment of a subscriber base to test different components of an email campaign and assess how they can be optimized. Through testing, marketers can find out what subject lines, offer types, pre-header text, imagery, time of deployment, etc. yield the best results prior to a campaign’s official deployment to the complete database.


Why is testing critical to an email program?

Email testing enables you to more effectively reach your subscribers by optimizing your email program and delivering a better customer experience. This, in turn, leads to higher open and click rates, continued subscriber engagement, and ultimately better ROI from your email marketing efforts.


How can marketers get started?

Before starting to test, marketers should be familiar with proper statistical practices to ensure valid results. Below are 3 things to keep in mind:

  1. Appropriate sample size: Verify that your subscriber base (and your resulting sample size) is large enough based on estimated expected response rates and is also representative of your subscriber base.
  2. Pulling your sample: Use the simple Random Sampling (SRS) method. This gives each subscriber an equal chance of being included in your test, therefore avoiding any bias in the test results.
  3. Measuring statistical significance: Marketers should strive to be sure that results are reliable and not due to chance. For instance, a 95% confidence level for a test means that if you ran the same test again, you are 95% confident that it will yield the same results.

What components can marketers use if they’re new to testing?

As a start, marketers can implement basic A/B testing to experiment with a number of simple email components. Here are a few ideas:

  • Subject Line: Arguably the most important part of your email, a compelling subject line will convince your subscribers to open your message. More subscribers opening your emails means a bigger likelihood for conversion. But how do you know which subject line will capture your audience’s attention? You can find out by testing different subject line components including personalization, character length, and offer inclusion.
  • Marketing Offer: Some offers may resonate more with your subscribers. You can test different forms of offers such as percent off, free shipping, or buy one get one free to determine what works best. For example, sending a message for “Free Shipping” may speak louder to subscribers than “20% off”.
  • Time of Day/Day of Week: Are your subscribers early morning risers or night owls? Do they engage more with your emails on specific days? By testing different times of the day or days of the week for email deployment, you can determine the best time to maximize engagement.

How can marketers optimize more than one email component?

If you have already mastered the A/B tests, consider adding multivariate testing to your email program. With multivariate testing, marketers can test multiple email components such as subject line, call-to-action, or offer type simultaneously, in the same deployment. Multivariate tests offer notable benefits, including:

  • Ability to test multiple email components in a single deployment, which is equivalent to several A/B tests performed at the same time
  • Opportunity to understand how different testing elements interact with each other, potentially yielding better results
  • Capability to isolate testing of program improvements to specific factors such as subject lines and calls-to-action, so marketers can better understand audience preferences.

With multivariate testing, marketers should keep in mind that the more components you test, the more email versions you’ll have. For example, testing 2 subject lines, 2 calls-to-action, and 2 offers will equate to 8 resulting versions of email campaigns to test, compare, and choose from. Therefore, having the right resources onboard and a large enough sample size will be critical in ensuring statistically significant test results.

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