What is Accessibility?


Accessibility means that no one is prevented from engaging with the materials you create because of a disability of any kind. No one will need to request a special accommodation to use your materials because they will already be accessible to anyone. Web accessibility helps ensure that anyone can perceive, understand, navigate, interact with, and contribute to the Web (from Web Accessibility in Mind (WebAIM)).

The Worldwide Web Consortium (W3C), an international organization that develops and maintains open standards for the Web has created the Web Content Accessibility Guidelines (WCAG) . These form the basis of most web accessibility law in the world and include four principles:

  • Perceivable: Information and user interface must be available to people in a way they can perceive, either through the browser or assistive technologies (e.g. screen readers, screen enlargers, etc.)
  • Operable: The user interface is usable, including all controls and interactive elements using either the mouse, keyboard, or an assistive device.
  • Understandable: Content is clear and limits confusion and ambiguity.
  • Robust: A wide range of technologies (including old and new) can be used to access the content (from WebAIM).

Why is Accessibility Important?

Inclusivity and Universal Design

Implementing accessibility standards ensures that people with hearing, visual, motor, and cognitive disabilities can use and interact with your materials. Accessibility in practice makes your materials easier to use and understood by all users.

Examples of accessibility in practice:

  • Using bold rather than red for emphasis increases legibility for most readers across different levels of vision.
  • Using captioning for video and audio allows people with hearing impairments to access the audio content;  it also allows people working in the library to read the content in a quiet space.
  • Adding alt text to images for screen readers also helps people with a slow internet connection or while browsing on a mobile device with images turned off to save bandwidth.


In the United States, accessibility is established by law, in the Americans with Disabilities Act (ADA) of 1990 and the Rehabilitation Act of 1973.

Additional Resources


Information on this page is adapted from: