Usability and Accessibility
Learning Goals of This Section
Explain what "usability" means.
Explain the overlap and commonalities between usability and accessibility.
Explain the differences between usability and accessibility.
In This Section:
Defining Usability
Commonalities
Differences
Defining Usability
Usability determines how easy a design’s user interface is to use and how functional a product or design is. Key components of usability assess:
How easy it is for users to learn the basic tasks of the interface;
If users can perform those tasks quickly;
If users can recall performing those tasks after time away from the interface;
The number of errors, the severity of errors, and recovery from errors in the interface; and
If the design satisfies users.
Usability testing evaluates how effectively the interface supports its intended purpose and how much time and effort users spend completing tasks.
The video below provides a helpful overview of the core principles of website usability. While it was created about ten years ago, the concepts it introduces are still widely used today. Since then, the field has continued to evolve, with greater emphasis on mobile-first design and accessibility. Modern usability discussions often incorporate guidance from the Web Content Accessibility Guidelines (WCAG) and place more focus on designing experiences that work well across different devices, technologies, and user needs.
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Video Transcript
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[Opening graphic]: Athena Brand Wisdom: Marketing Research and Strategy
Hi, I’m Jeff Hecker from Athena Brand Wisdom, and thanks for watching this short video on defining website usability.
In this video, I’m going to give you three different ways of thinking about what website usability is.
There are a number of different definitions of usability. The ISO definition of usability is the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use.
But there are, of course, more details and granular ways of thinking about website usability. One framework that I like is Whitney Quesenbery’s famous 5 E’s of usability.
According to this framework, a website with good usability should be:
Effective, which means users can do what they want
Efficient, which means they can do it quickly
Easy to learn
Error tolerant, which means that the site works to prevent errors or if someone makes an error, it helps them to fix the error
and Engaging.
Finally, no discussion of website usability would be complete without some reference to Steve Krug, who has written some really great and highly accessible books about usability.
When he defines usability, he says it really just means making something that works well - that is - that a person of average or even below average ability and experience can use it for its intended purpose without getting hopelessly frustrated.
Steve Krug enhances this definition with his presentation of his first law of usability, which is don’t make me think.
This means that, as much as humanly possible, a website should be self-evident, obvious, and self-explanatory.
He writes that designing for usability means working to reduce the amount of thinking that people need to do when using your site by making things as self-evident as possible.
The more people have to stop and think about how to do what they want to do, where to click, where to find things, what things mean, whether something’s clickable, etcetera, the more that confidence in a site and user satisfaction are eroded.
So, to be really specific then, what is a website usability issue?
Well, it’s anything that prevents task completion, slows the user down, takes the user off course, implies that things are okay when they’re not, or causes the user to misinterpret content.
It’s anything that makes errors likely or difficult to recover from, or prevents the user from noticing something important, or from taking the next step.
It’s anything that causes the user to look for a workaround or makes the user confused or irritated.
So, that’s an introduction to how website usability is defined. Thanks for watching!
[Closing graphic]: Athena Brand Wisdom: Marketing Research and Strategy
End of transcript.
Usability vs User Experience
Usability is a sub-discipline under User Experience design. It’s an important element, but it isn’t the entire user experience. Key points of consideration for each area are:
Usability
A design interface should be easy to use and allow users to become proficient.
Users should be able to easily achieve their goals through the design.
The interface should be easy to learn.
User Experience
Usability: Users can arrive on a site, use it easily, and complete a given task.
Useful content: A website should provide enough easily understandable information so that users can make informed decisions.
Desirable/Pleasurable Content: The user forms an emotional bond with the product or website.
Accessibility: A website should conform to accessibility standards to be accessible to users with disabilities.
Credibility: How much trust a user feels for a website (including levels of security and privacy) plays a role in the user experience.
User-Centered Design
User-centered design puts the user at the center of every part of the design and development process. Taking this approach means:
Involving users throughout the entire process, for example, through user research and user testing.
Taking an iterative approach and conducting testing after each stage to ensure things are working well in reality.
Conducting user testing for accessibility in the iterative cycles.
Commonalities
The same factors used to evaluate usability also apply to accessibility. Accessibility focuses on how usable and satisfying a product or service is for people with disabilities, including those who use assistive technologies. In usability terms, accessibility helps ensure that more people can use a product or design effectively, regardless of their abilities.
A Venn diagram consisting of two circles, one labeled usability and the other accessibility. The overlapping section shows the commonality between the two, that they focus on usability for everyone, including people with disabilities
Usability and accessibility often overlap. Many accessibility practices improve the experience for everyone, and strong usability can also support accessibility. For example, using high-contrast colors on web pages helps people with low vision or color blindness, but it also makes content easier to see in bright sunlight. Designing pages so they can be navigated with a keyboard supports people who are blind or who have motor disabilities, and it can also benefit users who simply prefer keyboard shortcuts. Likewise, usability practices such as clear language and intuitive design can make products and services easier to use for people with cognitive disabilities while improving the experience for all users.
Differences
It can sometimes be difficult to distinguish between usability and accessibility because the two are closely related. However, some issues are primarily usability issues, while others are specifically accessibility issues.
Usability issues tend to affect all users, including those with and without disabilities. These are problems that make a product or service harder for anyone to use. Accessibility issues arise when people with disabilities encounter barriers that prevent them from accessing or using a product or service.
In some cases, addressing accessibility issues can unintentionally create usability challenges. For example, if every image on a website is given very long alternative text, the images may technically be accessible, but listening to lengthy descriptions can become frustrating for users. Striking the right balance is important so that improving accessibility does not create new usability problems, and vice versa.
When documenting findings in usability test reports, it can be helpful to clearly identify accessibility issues, note which users may be affected, and reference the specific accessibility standards that are not being met.