A/A Testing: The Secret Weapon for Evidence‑Based Business Optimization

An A/A test compares two identical variations to validate the accuracy and reliability of the A/B testing process. By using variants A and A, you can determine whether an A/B testing tool can provide you with enough accurate data to determine which campaign elements are most effective.

Since there is no difference between the two variants, you should get similar test results. If you don't get similar results, the tool you're using may not be accurate enough to provide you with enough accurate data to improve the campaign.

A/A testing also has other purposes. For instance, you can use it to determine a baseline conversion rate to compare to your campaign. Then, you'll understand the difference between an average and a high conversion rate and can determine whether one variation is more effective than another.

A/A testing comes before A/B testing and is primarily used to determine the accuracy of a new split testing tool.

A/B testing and A/A testing have different purposes. For instance, A/A testing compares the same page or elements, while A/B testing compares different pages or elements.

With A/A tests, there are no differences between the variables. Every aspect of the experiment is the same. However, when you run an A/B test, you compare two or more versions of an ad, email, or landing page with a single variable changed in each. For instance, you might compare:

• CTAs
• Colors
• Buttons
• Design elements
• Copy

In addition, while A/A tests are used to determine the accuracy of a testing tool, A/B tests use that testing tool to determine which variables can significantly impact campaign performance and increase conversion rates. In A/B tests, you determine which variables, elements, and copy perform best and use those to create your campaign.

When should you use A/A testing?

Again, A/A testing is primarily used to ensure the accuracy of an A/B testing tool. There are plenty of tools out there, but you can't know if they're accurate unless you run A/A tests.

The three instances when you might use an A/A test include when using a new testing tool, establishing a baseline conversion rate, and setting your minimum sample size to reach statistical significance.

Determining a testing platform is working correctly

When you use a new A/B testing platform, you must ensure its accuracy. A/A testing can help you determine if a new tool you've never used before actually works correctly. If there's a significant difference in test results, it may indicate issues with the software.

With A/B testing, you want the results to yield a clear winner. However, you don't want a clear winner with A/A testing because it means there's a discrepancy in the test data since the two variations are identical. If you find a significant difference in the data, it could mean that the tool is being used incorrectly or that it's inaccurate.

Establishing a baseline conversion rate for a page

Before running an A/B test, you should know the baseline conversion rate that helps you understand which variation performs best. By comparing two identical variations of a campaign, you can determine the expected conversion rate before changes are made.

As long as the results are accurate and there are no statistically significant differences in the data once the experiment is complete, you should have a general understanding of your baseline conversion rate that represents the expected campaign conversion rate without any changes.

Setting a sample size for A/B testing

A/A testing requires a larger minimum sample size than A/B testing, but it can help you set a sample size for your tests. By examining data from testing two identical variants, you can observe the variability for estimating the required sample size for A/B tests.

For instance, if the A/B testing tool yields significantly different results for identical variants in A/A testing, it may mean your sample size isn't large enough. A small sample size may not be sufficient enough to measure your KPIs and determine if an A/B test is truly accurate, meaning you might miss out on opportunities that could impact results.

On the other hand, a larger sample size gives you the most accurate data.

Flaws of A/A Testing

A/A testing can help businesses ensure the accuracy of the A/B tools they use and how they use them while determining sample size and establishing baseline conversion rates. Unfortunately, no testing method is perfect.

A/A testing assumes that two identical pages or campaigns should produce similar results, but this isn't always the case because various factors can affect test accuracy. For instance, one variant might perform better than the other, but that doesn't necessarily mean the tool is ineffective.

A/A testing also requires a larger sample size than A/B testing because you're testing two identical versions. In addition, using an A/A test to determine a conversion rate benchmark doesn't necessarily mean your A/B tests will yield the same results. Even if you've set up your experiment perfectly, external factors like buyer preferences, consumer behaviors, and market conditions can affect conversion rates during A/B testing.

You can run an A/A test using any A/B testing tool since you're essentially just testing variant A versus another variant A. Then, to determine if your A/B testing tool will yield accurate results, you can set up your first A/A test using the following steps:

1. Set goals: Determine what you want your A/A test to tell you. Are you trying to determine the tool's accuracy or set a baseline conversion rate for a campaign?
2. Segment your audience: The whole point of A/A testing is that everything is the same, including your campaign and target audience. You can create two identical segments of the same size and characteristics to get the most accurate results.
3. Create your test: Once you've segmented your audience, assigning each half to a page, you can create your A/A test by showing both segments the identical versions of the campaign.
4. Measure results: After the testing period ends, you can analyze the results and determine whether your campaign successfully helped you reach a conclusion.

How to interpret the results of an A/A test

There are two things that can happen when measuring the results of your A/A test:

1. The results are similar.
2. The results are different.

If the results are similar, you can safely assume the A/B testing tool is accurate and can provide enough performance data to make the right decisions for your campaign going forward. It's important to note that you may not get exactly the same results because of the random nature of the testing environment.

Ultimately, there should be no A/A experiment winner because you're testing identical versions. Instead, results should be inconclusive. However, statistically significant differences in results may mean there's an issue with the tool or how the experiment was set up. If you find significant differences between the two identical versions, you shouldn't assume the analytics tool is inaccurate.

Instead, you might want to review how your experiment was implemented. For instance, you may not have segmented your audience into identical groups, leaving room for error. It's possible you determined the audience based on age and location.

However, you might not have considered how gender can affect your results. An audience of 20-year-old men in the US is different from an audience of 20-year-old females in the US. Other common mistakes include not having a large sample size and ending the test early, both of which can affect your results and lead to statistically significant differences in data between the two variations.

Use A/A tests to strengthen your A/B testing

Incorporating A/A testing into your A/B process can help you determine whether a tool or experiment is effective and make data-driven decisions to enhance your marketing campaigns. While A/A testing has limitations, it can provide a valuable quality assurance measure that ensures trustworthy results.

Put your data to work with Mailchimp's analytics, reporting, and AI-assisted tools. Our comprehensive suite of testing and analytics features empowers businesses to conduct A/A and A/B experiments that can help you gain valuable insights into your marketing campaigns. Sign up for Mailchimp today.