Accessibility ABCs 3: Get started with accessibility

The four principles

Illustration of a person sitting on a black floor in front of an orange wall. They are wearing a blue shirt over a white tshirt, blue trousers and white shoes. They have black hair. There are two large question marks either side of their head.

There are several guides, checklists and documentation on accessibility, but for the purpose of this guide, we are starting with the Web Content Accessibility Guidelines (WCAG). These guidelines were developed by the World-wide Web Consortium (W3C), the governing body of the web and are based on four principles:

  • Perceivable information: Information that users need must be available to one of their senses.
  • Understandable information: Content should be clear and comprehensible to limit confusion and ambiguity.
  • Operable service: Users should be able to interact with all controls and interactive elements using either the mouse, keyboard, or an assistive device.
  • Robust service:  Content must be robust enough that it can be interpreted reliably by a wide range of technologies including old and new user agents and assistive technologies.

Three questions to start

Ask yourself: 

  • Does my service respond to the four principles?
    • Hint: Ask the same question for each page of your website or application.
      Keep both your content and design in mind as well.
  • When did my team start incorporating accessibility?
    • Hint: It is never too early for accessibility to be in your focus.
  • Did you test your service? How?
    • Hint: What your test group looks like?

Next: Best practices applied to case studies
Previous: What do we mean by accessibility?
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