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Quantitative Testing in UX

Adam Fard
Adam Fard, Co-founder & Head of Design
Quantitative Testing in UX

When it comes to assessing the experience of a product, UX specialists have an entire arsenal of methods to choose from. As diverse as they may be, all these types of tests fall into two major categories—qualitative and quantitative. 

While the former revolves around the how and why of an experience, the latter provides us with an understanding of how often an action has been performed, how many users have performed an action, and a variety of other experience parameters that can be expressed in numbers.

This article will focus on the peculiarities of quantitative testing, the value that it provides, and the settings where it’s most useful. 

Let's dive right in, shall we? 

What is quantitative testing?

Fundamentally, quantitative testing provides designers with an insight into the usability of a product or service. 

Most of the time, quantitative usability tests revolve around tasks that users perform while interacting with an interface. This allows designers to collect numeric data about their performance and, as a result, understand the areas of an experience that may require additional attention and, possibly, tweaking. The outcomes of these tests can also be used for reporting and benchmarking. 

Of course, the results that quantitative testing yields are often generalized and lack depth compared to qualitative methods, but on the other hand, numbers are much more reliable than subjective accounts. 

When should you use qualitative testing?

The rule of thumb when it comes to testing is that qualitative methods are used throughout the entire design process of a product, whereas quantitative methods are used at the beginning of the end of the cycle. 

Part of the reason for this distribution revolves around the fact that qualitative methods allow designers to gather a deeper understanding of their user's experience with the earlier iterations of a product, while quantitative methods are useful when they’re looking to confirm or disconfirm theories that arose as a result of qualitative tests. Similarly, they’re useful at the beginning of the design process by allowing to surface trends that can further fuel qualitative research. 

Another essential function of quantitative testing is calculating the ROI of a product or its redesign, which allows stakeholders to gather a better understanding of their business needs. 

Measuring usability

The purpose of measuring usability is to provide insight into how people interact with your product, which should, as a result, inform the changes that need to be done to better their experience. This ensures that a product is intuitive and easy to use. 

Let’s take a look at a few ways quantitative testing can assist in achieving this. 


Measuring the efficiency of a task typically revolves around calculating the average time it takes to execute a particular task.

A basic way to find out the time a user needed to complete a task they were presented with is to subtract the start time of the task from the time when they finished working with it. 

A significant part of improving a product’s usability is ensuring that basic tasks take less time, since it generally correlates with ease of use and intuitiveness. 


Satisfaction is a critical dimension of user experience and it can be assessed in a quantitative manner as well. Typically, this is done via questionnaires that are provided to users after they’ve participated in usability testing. There are many ways these questionnaires can be structured, here are five of the most commonly used formats: 

  • ASQ: after scenario questionnaire 

  • NASA-TLX: NASA’s task load index

  • SMEQ: subjective mental effort questionnaire

  • UME: usability magnitude estimation 

  • SEQ: single ease question 

These questionnaires are normally provided to users immediately after they’ve attempted to complete a task, in order to measure usability, i.e. assess how complicated and satisfying they think it was. 


Measuring effectiveness revolves around understanding the accuracy and completeness with which the participants have managed to execute the tasks you’ve provided them with. 

This is generally done using two common usability metrics—success rate and the number of errors that occurred throughout the test.  

Task success is a metric that expresses the percentage of the test participants that we're able to successfully execute the tasks provided to them. While this is a fairly straightforward metric that doesn’t really provide too much insight on the finer details of a person’s experience while working on the task, it remains a crucial surface-level indicator of usability issues. 

Measuring behavior

Understanding the intricacies of user behavior is an invaluable asset for any product. It allows businesses to extract insight into their potential customer's preferences and needs, allowing them to gain a significant competitive edge, retain users, and eliminate a substantial part of guesswork out of their user experience efforts. 

A/B testing

This method of testing is exceptionally useful when comparing different versions of an interface or page, in order to identify the one that serves the users’ needs better and provides better overall performance. 

This testing method allows organizations to gather lots of data on their most relevant KPIs, like conversion rates, allowing them to make calculated design decisions. This is precisely why big companies like Amazon and Google invest a lot of time and effort into A/B—numbers speak for themselves and conversion rates don’t lie. 


Heatmaps are an awesome tool when it comes to testing multiple prototypes, especially in terms of engagement, clarity, and whether users find them useful. This testing method allows you to understand where users click most, see how far they scroll on your page, and identify the things that catch their attention. 

While there’s a variety of heatmaps used across industries, the most common ones are:

  • Click maps—show the areas where users click or tap on an interface;

  • Scroll maps— show how far users scroll;

  • Move maps—show users’ mouse movement on an interface;

Heatmaps are an excellent tool when it comes to:

  • Understanding what motivates your users to take action;

  • Ensuring that your CTAs are positioned properly;

  • Identifying patterns in your users’ behavior on your site; 

It’s important to underline that heatmaps generally need a few weeks worth of data to show meaningful results.

Conversion funnels

Conversion funnels allow designers to quantify the percentage of users that complete every individual step of the user journey to reach a particular goal. This is an excellent way to measure the overall performance of your site, allowing you to assess the quality of your user's interaction with the site. 

Conversion funnels typically consist of three parts—top, middle, and bottom. Users ascend from the top—the broadest part of the funnel where all the people interacting with your product start their journey—and gradually move down to the bottom as they complete their path. 

Naturally, the lower part of the funnel will have less actual customers, as people gradually drop off for one reason or another—which is totally fine. However, businesses should keep track of the percentage of users that drop off throughout their progression through the funnel. High drop-off percentages may suggest that there’s an issue in their interaction with your product, and addressing this can substantially improve their satisfaction with your brand, as well as address a variety of usability issues. 

Bottom line

Quantitative testing is a vital part of ensuring the usability of your product. While it may lack the detail and depth of qualitative data, it remains critical when it comes to validating theories and establishing bigger picture trends and patterns. 

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