What Is A/B Testing?

Written by Coursera Staff • Updated on

A/B testing, sometimes called split testing, is a marketing strategy that can improve campaigns and, in turn, drive customer engagement and sales. Explore its uses and benefits for a better understanding of the practice.

[Featured Image] A marketer sits at her laptop at her desk and goes over the results of AB testing conducted by her team.

A/B testing compares two versions of an application, email, website, or digital element like a headline to see which is more successful. It's often used in digital marketing, where you create two different versions of something, like an email, and send version A to one group and version B to another. You can see which version is more effective by viewing metrics, like the number of people who clicked links or made a purchase.

At the root of A/B testing, you glean helpful information to make informed decisions and optimize the customer experience. Discover more about who uses A/B testing and why, along with the potential benefits and drawbacks, for a broader understanding of why this essential strategy should be a continual addition to any marketing practice. 

Who uses A/B testing?

The results of A/B testing, sometimes called split testing, provide valuable data about what is or isn’t working with the test subject. A/B testing, which can be used in various experiments across different industries, including tech companies, startups, and marketers, commonly uses it. 

Tech companies

Tech companies use A/B testing to improve a customer's experience. If a company is developing software, for example, it can use split testing to enhance the UX or user experience. They might compare the location of a CTA or call to action, for example, to see if its placement impacts the number of times it's clicked. By running a series of tests, developers can make educated changes to the software to please users. 


While start-ups can use A/B testing to improve their website and marketing efforts, you can also use it to test new ideas. When a start-up embraces this excremental culture, they're willing to test anything from product modifications to in-office perks like extending lunch hours. Employees are happy because it validates their ideas, and managers are happy because they make decisions based on actual data. 


Grabbing customers' attention is among the primary tasks marketers face, which can be challenging. Marketers run tests on their websites, emails, and content, looking to make minor adjustments that could result in increased revenue. Like all A/B tests, marketers pick one thing they'd like to test, like a piece of website copy, a picture in an email, or the title of an eBook. In this scenario, they would split their audience and show a different version to each group to see which produces the most remarkable outcomes. 

What is A/B testing used for?

A/B testing helps you measure cause and effect, which means you can see the consequence (or effect) or something that happens (a cause). With this information, brands can identify what's valuable to customers and use the data to predict potential preferences and behaviors. 

You can also use A/B tests to obtain decision-making data by testing one thing at a time. So, for example, if you want to test an email campaign, you wouldn't create two entirely different versions; you'd make one element of it different, like the header image or subject line. Given the nature of this kind of testing, marketers often test specific aspects of a website or campaign. Typical components to test include: 


  • CTAs: Size, color, font, shape

  • Headings: Size, font, color, placement

  • Images: Varying pictures, colors, realistic versus animated, placement

  • Product descriptions: Varied lengths, formats

  • Forms: The number of questions asked, including a progress bar, formatting

Social media

  • Use of video or picture

  • Hashtags

  • Post length

  • Use of coupon code


  • Personalized text

  • Email send times

  • Email subject lines

Pros and cons of A/B testing

Using A/B testing eliminates a substantial amount of guesswork, allowing you to know exactly what does (and doesn’t) work for an improved return on investment (ROI) and enhanced engagement. As you consider A/B testing, weigh the pros and cons of the process, which include:


Quick results

You can run an A/B test reasonably quickly and get immediate results. These short-order tests can guide marketers, website designers, or product developers to ensure their efforts are adequate for their customer base. 

Improved metrics

Both engagement rate and conversion rates can increase with A/B testing. As you test components, like the size of a call to action button, you see which one customers respond to. As a result, you'll likely see more customers click on it, which drives engagement and, in turn, drives conversions.  

Reduced risk

By using A/B testing, you can make informed decisions. Rather than building an entire website and learning about issues upon completion, you can identify improvements as you go and reduce the risk of large-scale, time-intensive changes. 

Enhanced content

By taking the time to test content, you can make necessary improvements for a higher-quality end product. Let's say you test copy within an email or on a website. Tests will show you which version is best and, as a result, improve your copy. Testing allows you to evaluate and tweak your content so it's effective for customers.  


Specific goals yield limited-scope results.

To succeed, you need a specific thing to test, usually a small piece of a product, website, or marketing campaign. You can test an email subject line, for example, and while the results are helpful, it only provides direction on that specific item, not the entire email. 

Short-term results

While you can glean valuable information from A/B testing, the sentiment from your audience could change. What works today could be less effective in six to twelve months. When a brand commits to A/B, it's with an understanding that it should be a continual, consistent, ongoing process.  

Requires time and effort

A/B testing can provide data-based guidance, but it does take time to set up, execute, and track each test. For instance, if you're testing email copy, you'll need to create two versions, segment your lists, review the results, execute the results, and keep a running log of lessons learned from testing.  

Best practices in A/B testing

Successfully executing A/B testing requires identifying the appropriate elements to test, choosing those that you can adequately compare to various versions, and scheduling tests when both “A” and “B” elements experience similar traffic volumes. As you consider what to test, follow these suggestions to help ensure you follow best practices:

Have a goal in mind

Before you pick something to test, consider what you're trying to achieve. For example, if you're testing email marketing, your goal might be to boost click-through rates. With this goal in mind, you'll test only items you believe impact a person clicking the call to action. 

Test one item at a time.

A/B testing works best when you test one specific item against another. By testing one thing, you can be sure the improved results stem from the one thing you changed. Attempting to test more than one thing at a time will leave you wondering which change contributed to its success. 

Give your tests time.

Testing provides quick insights, but you must invest time in each test to get statistically valuable data. Ideally, you'll test at least a week, but two weeks is usually the industry standard. Two weeks ensures accurate data and gives you confidence to proceed with the findings. 

Ask others for input.

To expand your testing possibilities, consider asking others for feedback. Ask your colleagues what they think you should test or collect customer feedback that can help guide your tests.

Get started with Coursera.

A/B testing is a critical strategic element you can use to optimize websites, emails, applications, and more. Explore marketing analytics further and hone your skills in this industry with online classes on Coursera, taking an online class on Coursera, like Assess for Success: Marketing Analytics and Measurement. In this course, you'll evaluate metrics against performance goals to strengthen your marketing strategies, which can help further your skill set. Another excellent option, Introduction to Marketing from the University of Pennsylvania, can help you gain foundational knowledge in marketing strategies and customer satisfaction.

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