Wiklund's Perspective: User Testing versus Usability Testing -- What’s the Difference?

By Michael Wiklund

People new to human factors might wonder about the difference, if there is any, between the terms user testing and usability testing. My answer is always disappointing and annoying, “It depends.”

What’s the difference between user testing and usability testing?

I hear these terms used synonymously in casual conversations and professional presentations alike. Maybe in an earlier stage of my career, I used the terms user testing vs usability testing synonymously as well. However, I don’t anymore. My carefully considered choice is based on the same reason that I don’t use the term user error anymore (with thanks to William Hyman).  I speak of use error because a term like user error, and user testing, places the focus on the user’s performance instead of the product or system.

“The term use error has recently been introduced to replace the commonly used terms human error and user error. The new term, which has already been adopted by international standards organizations for medical devices … suggests that accidents should be attributed to the circumstances, rather than to the human beings who happened to be there.” 

Understanding Usability Testing Terminology

Fair to say, people intend the term user testing to describe an evaluation focused on the quality of interaction between people (users) and a product (e.g., physical fitness app). However, it literally sounds like the test evaluates the user’s capabilities, such as (1) the number of push-ups a person can do in 2 minutes, and (2) how many numbers a person can memorize and recall correctly after a given memory decay period. In these examples, test results would depend largely on an individual’s physical and mental capabilities. Although it might only shift the tone, I and many more human factors specialists use the term usability testing instead.

The terms formative testing and summative testing have also entered the lexicon, as has human factors validation testing (with thanks to the FDA). Each of these terms denotes usability testing. You are looking for opportunities to improve a product in the case of formative testing. You are looking to determine if a final design is safe and effective in the case of summative and human factors validation testing, which are the same thing.

When to use the term usability testing

Usability testing calls for individuals to engage in use scenarios. Use scenarios can involve a certain type of person, use environment, performance-shaping factors (e.g., time pressure, loud background noise, limited training), and an objective (i.e., job to be done). Such an evaluation focuses on how well a given product or system performs, which is revealed by the individual’s performance. Sure, different individuals may perform at widely varying levels, suggesting there is a testable human element to this kind of evaluation. However, the goal of usability testing is to identify the strengths and opportunities to improve the test item, not the human.

While there is a clear differentiation between user testing and usability testing, I acknowledge the fact that some industries might be locked into one term or the other and are unlikely to change. For example, I would not be surprised if an advertisement agency planning to produce a 30-second commercial completed some user testing. Then again, they might choose to call it strategic assessment, pre-testing, or pre-screening. To each industry their own.

HF specialists at Emergo by UL use the term 'usability testing'

In the business of human factors, particularly in relation to evaluating products (e.g., medical devices, drug delivery devices, consumer products, industrial products, and software applications), we tend to stick with the term usability testing. You’ll find the term in the title of leading textbooks, the special interest groups or professional associations, and various evaluation plans and reports.

Yes, the Human Factors Research & Design (HFR&D) specialists at Emergo by UL are “Team Usability Testing.”

Michael Wiklund is Leader of the Life Sciences Industry Practice at UL Solutions.