Anastasiia Paskar August 22

Usability testing and accessibility (WCAG 2.1)

It might seem that usability and accessibility are the same since they both relate to the website experience. So what is the difference between them? Your website might be accessible, but it may not be usable. Usability is tied to the satisfaction and efficiency a person experiences when engaging with your website. Conversely, a website can be considered usable. Yet it may ignore the accessibility guidelines geared toward the disabled community. Let’s now try to understand both of these testing types in more detail.

An Overview of Usability testing and accessibility 

Usability testing, also called user experience testing. It measures the overall user satisfaction of a website/app. Focusing primarily on user interface interactions and successful completion of tasks. To check usability, you test button interactions, form fields, navigation, and user flow. Ideally, the process should take the user to their destination with as few clicks as possible. 

In accessibility testing, you can test how easily the website’s content can be accessed with keyboard-only navigation devices. So that the people who have permanent disabilities such as vision, hearing, cognitive or physical impairments, can have equal access to the website content and successfully complete tasks. For example, accessibility testing can include ensuring appropriate contrast ratios of content and background colours, readable font sizes, and the inclusion of alternate text for images. Accessibility and technical standards, such as the widely accepted Web Content Accessibility Guidelines (WCAG), can serve as a solid foundation, but nothing replaces real-world testing to establish true usability.

Principles of usability testing

Here are the quality components of usability testing as defined by Nielsen Norman Group

  • Efficiency: Users can perform tasks quickly.
  • Learnability: Users can accomplish basic tasks the first time they encounter the interface. 
  • Memorability: Users can reestablish the same proficiency after not using the design for a long time. 
  • Errors: Users are provided with helpful information to correct them. 
  • Satisfaction: Users have a pleasant experience using the website . 

Principles of accessibility 

The principles recommended for digital accessibility compliance as defined by the WCAG are as follows: 

  • Perceivable: Users must be able to perceive it in some way, using one or more of their senses.
  • Operable: Users must be able to control UI elements (buttons must be clickable in some way — mouse, keyboard, etc.).
  • Understandable: The content must be understandable to its users.
  • Robust: The content must be developed using well-adopted web standards that will work across different browsers.


Better accessibility has become a critical aspect of modern technologies. Nowadays, websites and applications should be digitally accessible to all users. Usability and digital accessibility testing play a vital role in achieving this goal. Usability testing helps uncover issues. And it helps get feedback from the audience who use the system during the test. While accessibility testing offers a pleasant experience to a diverse audience, including people with disabilities.