In terms of digital accessibility, usability refers to the quality of a user’s experience regarding a product, device, application, or website. The more usable a digital experience is for everyone, the better their overall user experience will be. Usability refers to questions like, “How easy is the product to learn to use?”, and “How satisfied was the user with that process when it happened?” Because every digital experience is different, there is no characteristic that is singularly responsible for the quality of the experience. That is why usability is usually associated with five characteristics.

What are the five characteristics of usability?

The five characteristics of usability, according to Nielsen Norman Group co-founder and user advocate Jakob Nielsen are:

  • Learnability
  • Efficiency
  • Memorability
  • Errors
  • Satisfaction


On a website, application, or other digital platform, learnability means that the design is intuitive and easy for a brand-new user to figure out. Intuitive design follows specific patterns and styles that we, as humans, can recognize and respond to. While every website may be organized differently and function differently, there are common themes—a top navigation bar, a footer with more information, etc. While there’s no harm in having a unique, exciting web or digital layout, it should not be to the detriment of learnability. If visitors cannot learn how to navigate through or use a digital experience to get what they need, be that information, a service, or a product, they will leave in favor of an experience they can learn to use.If a software service simply cannot exist without some degree of a learning curve, establishing a tutorial or walkthrough can help increase learnability.


Many have heard a task described as “like riding a bike;” even if someone hasn’t done it in a long time, muscle memory will take over and help them fall into the routine. Suppose a user returns to an app, website, product, or platform again after an extended hiatus. In that case, a consistent, memorable user interface and user experience design makes it so that they can jump back in without needing to relearn everything. In this way, consistent design is key not only to memorability but to learnability and efficiency as well, demonstrating how different aspects of usability are interconnected.


Efficiency is concerned with one core question: after a user has learned, or remembered, how to use a website or platform, how easily can they carry out the task they came to accomplish? In other words, how many interactions (e.g., clicks), steps, or pages must a user navigate through to access what they’re looking for? Usable digital design should take into account the efficiency of specific tasks.


User error is bound to happen. However, a usable digital experience places constraints and offers suggestions to a user to help prevent these errors. A usable website will also be flexible, meaning that it can handle some margin of error without completely “breaking” or stopping a process in its tracks. For example, say a company’s shipping policies require addresses to be formatted with the extended 9-digit ZIP code. Most people only know their basic 5-digit ZIP. Instead of defaulting to an error when a 5-digit ZIP code is entered in the address field of a form, a website designed for usability will have enough margin for error to auto-lookup and fill in that space for the user, allowing them to move on to the next task easily. In digital design, another part of usability is creating an interface that supports swift, effortless correction when an error occurs. Usability considerations like this are not only helpful in the event of a hasty typo, but can be beneficial for those with learning or cognitive disabilities, or for those who may not be searching in their native language.


In terms of usability, satisfaction doesn’t always mean that the end product is precisely what the user wanted—though that is important to a digital experience’s success. For usability, satisfaction means that a design is pleasant to use, and it answers the question, ”Did the user enjoy interacting with the platform?” This is subjective, and it will be impossible to please everyone on a universal scale. However, a designer should strive to create an experience that minimizes frustrations and annoyance. Things like unnecessary pages, pop-ups, difficult-to-navigate interfaces, hard-to-see or unpleasant color schemes, and unclear directions should be avoided to improve user satisfaction and boost usability.

What is usability testing?

Usability testing is the process of putting a website, app, or other digital product through a series of evaluations to ascertain how difficult it is to carry out a task. Usability testers, which may include or be guided by researchers or experts, will make active notes to provide their feedback about the process. The participants’ feedback then turns into research insights, which leads to the next set of requirements for the building of that digital experience.Usability testing performed specifically to investigate an experience’s accessibility is often called use case testing. This type of testing is performed on a website, app, or other digital experience by users with disabilities using assistive technology, accessibility features, or other strategies that a person with that disability would commonly use, to determine whether that experience contains barriers to access or could be improved for people with this type of disability.

What is the difference between usability and accessibility?

According to the Worldwide Web Consortium, accessibility “addresses discriminatory aspects related to equivalent user experience for people with disabilities”, while usability “is about designing products to be effective, efficient and satisfying” and “may include general aspects that impact everyone and do not disproportionately impact people with disabilities.” Some may read these definitions and come away with the impression that usability is a broader concept than accessibility, and that accessibility is a subset of usability focusing on people with disabilities. This may lead to the conclusion that a website or other digital experience can be usable (for at least some users) even if it’s not accessible. At Level Access, we advocate that the relationship should be thought of the other way around. If you want your digital experience to be usable, accessibility isn’t a nice-to-have—it’s a must. Learn more about why accessibility should be embedded in the foundation of every digital experience.