Usability Testing vs. A/B Testing: When to Use Each?

Usability Testing vs. A/B Testing

You need both usability testing and A/B testing if you want to increase your conversion rate. Both of them aim to understand customers’ needs to give them the best user experience. Businesses often tend to distinguish between these two; however, you should know that they complete each other. 

But you’re here to know when to use each, right? This article will review usability testing vs. A/B testing, their pros, cons, purposes, and alternatives. 

Note: You can conduct usability tests easily by monitoring user behavior. WatchThemLive is a solution that captures their behavior. We explain more about it, so keep reading to find out. 

Usability Testing Definition 

Usability testing makes understanding users’ behavior and needs easy with qualitative data. It allows you to understand what works and what doesn’t by interviewing and observing test participants. Since usability testing requires participants, it gives you more accurate data, but you can also conduct it by recording visitors’ behavior if recruiting participants is not possible for you.

You can do this by session replay software. WatchThemLive offers the best session replays that allow you to see visitors’ interactions with your website.

For example, if %30 of people add an item to their shopping cart, but only %10 of them purchase, it shows that there is something wrong with your purchasing process. With WatchThemLives’ session replays, you can see exactly what’s the problem. Maybe users drop out after they had to sign up for purchasing? Or maybe your shipping is too expensive? Or you don’t have the payment method they’re looking for? You can exactly see at what stage users drop out and take immediate action. Watch this video to see how they work:

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Now, let’s review usability testing’s pros and cons: 


  • Usability testing comes to the rescue when there’s a disagreement among team members about what works and what not. 
  • You will have a deeper understanding of the user.
  • It uncovers different data sources that will help you find more room for improvement.
  • It doesn’t take much time to run the test and get results.
  • There are no statistical errors in usability testing.
  • You can make real improvements since the test is based on your target audiences’ direct feedback.
  • When the prototype is examined through usability testing, the chances of any friction and usability problem in the launched design is reduced. 


  • The results you get from usability testing are theoretical, and you have to invest lots of time and money.
  • Since the results are just qualitative, you won’t have quantitative data and can’t estimate the revenue of your findings.
  • Participants might behave differently in their own natural habitat than during usability testing. What you need is natural interactions because people use your product while doing their daily routines.
  • The results are based on a few participants’ behaviors and not your whole target audience. So it might not apply to all of your customers.
  • Usability testing won’t tell you how to fix the issues exactly. You have to find solutions by interpreting participants’ words and behavior. 
  • Participants might not pay as much attention when they are completing a task just for the sake of usability testing. For example, if they’re purchasing a product for real, they put all of their attention into it.
  • The results might not be very accurate since some people only participate in your test for the sake of money. 

Usability Testing Purposes

Usability testing improves your design by tracking visitors’ behavior. You can understand so much from the way users interact with your website. For example, you can see if users can’t find your ‘contact us’ button because it’s not placed in a good place. After that, you are able to implement changes that will result in faster and easier task completion.

A/B Testing Definition 

A/B testing compares the functionality of two different versions of your website. While A/B testing, a portion of traffic is sent to version A, called control, and the rest to version B, known as the variation. After that, you can see whether your changes were positive or not by using statistical analysis. 

Below you can find the pros and cons of A/B testing: 


  • You can see which version is working better easily by the number of conversion rates.
  • You are able to monitor the number of clicks, conversion rates, etc.
  • It allows you to test all of the elements of your website. 


  • You need new ideas to implement in the latest version, and choosing between these ideas not knowing which one of them might work better is a hassle. If you have lots of traffic, you can conduct several tests, but they can all perform equally, and you won’t discover the most impactful design element. Therefore, it’s possible that you won’t get any results.
  • Since A/B testing is quantitative, you can’t understand the reason behind why users choose what they choose. 
  • You need a large number of visitors for statistically accurate data.
  • It takes a lot of time to conduct A/B testing since you have to test different ideas.
  • There is a high chance of facing statistical errors while running an A/B test.
  • You’re not considering user behavior; only your assumptions are being tested. 

A/B Testing Purposes

A/B testing compares two versions of one website to see which one performs better. For example, your goal is to drive more conversions, and for this purpose, you want to know whether a video performs better on your landing page or an image. Now run an A/B test to see which one is having more conversions.

All in all, the purpose of A/B testing is to increase conversions and sales, reduce bounce rates, improve content engagement and reduce cart abandonment

Usability Testing vs. A/B Testing: When to Use Each?

In a nutshell, you run usability testing when you want to know the “why” behind users’ actions. Meanwhile, A/B testing is used when you want to know what performs better on your website.

For example, you have set a goal to attract more visits for a product category and increase the conversion rate. You’re wondering if a horizontal menu or a hamburger menu would perform better in helping reach your goal? You run an A/B test to see which one gets more attention here. 

On the other hand, designers use usability testing when they want to know why visitors are behaving a certain way. For example, you want to know if your customer journey map is smooth enough? Can customers complete tasks hassle-free? Is there something that distracts them from going down your funnel? This means that you are tacking users’ interaction with your product.

In usability testing, you obtain qualitative data, but A/B testing gives you quantitative data about the number of people who completed a task successfully.

Now that you know when to conduct usability testing and A/B testing, you should know that the best results are achieved when these two work together. First, build your website based on user behavior, then run A/B tests to see which designs works better. When you combine both qualitative and quantitative data, you’ll see real growth. 

Alternatives to A/B Testing

A/B testing won’t work properly without a large number of users, so what can you do instead? We will review the alternatives to A/B testing here:

1. User Experience Research

With user experience, you are able to collect both qualitative and quantitative data. The good thing about user experience research is that there’s no need for lots of traffic and controls. You can monitor user behavior by using software such as session replay

By using a behavior analytics tool such as WatchThemLive, you will have access to detailed analytics about users as well as session recordings. For example, you can see the number of their sessions, events, device, country, browser, and so much more. Knowing this information helps you provide a personalized experience for your customers. 

watchthemlive analytics

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2. Customer Interviews

Interviews can provide more in-depth data than surveys since you can include open-ended questions. Customers who regularly visit your website and have already gone down through your funnel are the best ones to interview. 

3. Polls/Surveys 

Surveys are an A/B testing alternative that let you gather user reviews and engage them easily. However, if your survey is boring, you won’t get many results as a lot of people won’t participate. You can utilize survey software to speed up things.


In the end, whether you decide to choose usability testing or A/B testing solely depends on the question you have. Do you need the answer to how much? Conduct A/b testing. Do you need the answer to why? Conduct usability testing. 

With usability testing, you’re monitoring user behavior, but with A/B testing, you’re just testing your own assumptions. So it might not be very accurate compared to usability testing. Keep in mind that combining them will do the trick! 

Start your usability testing with WatchThemLives session replays now. Sign up for FREE and see their affordable plans. 


Good luck!

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