WCAG Principles and Implementation

The Web Content Accessibility Guidelines (WCAG) has 4 guiding principles. Implementing them places people at the center of your web site.

The W3C Web Content Accessibility Guidelines 2.0 (WCAG), level AA, serve as Web accessibility standards for the University of Minnesota. If any of its principles are not true, people with disabilities will not be able to use your site.

Diagram: WCAG 2.0 Principles
Figure 1: WCAG 2.0 Principles

The WCAG Principles

The principles, Perceivable, Operable, Understandable, and Robust are often referred to by the acronym POUR.

  • Perceivable means that information and user interface components must be presentable to users in ways they can perceive.
  • Operable means that user interface components and navigation must be operable.
  • Understandable means that information and the operation of user interface must be understandable.
  • Robust means that content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.

Implementing the Principles

Making a Website Perceivable

People must be able to perceive the information being presented. It can't be invisible to all of their senses. According to the WCAG this includes items such as:

  • Providing text alternatives for any non-text content for instance using short text alternatives for all images as well as long descriptions for complex images
  • Providing alternatives for audio and video, such as captioning and audio descriptions
  • Not playing audio automatically
  • Using good structure for web pages such as real headings, real lists, and proper data tables for data
  • Making it easier for users to separate foreground from background for instance using good contrast and plain rather than busy backgrounds
  • Not relying solely on color to present information
  • Presenting content in a meaningful order

Making a Website Operable

People must be able to operate the interface (the interface cannot require interaction that a user cannot perform). According to WCAG this includes items such as:

  • Ensuring every link's purpose is understandable
  • Using clear and real headings and labels
  • Using helpful and clear page titles
  • Making all functionality available from a keyboard
  • Ensuring keyboard focus is visible and clear
  • Providing people enough time to read and use content
  • Providing a working "Skip to Content" link
  • Providing ways to help users navigate, find content and determine their location, such as breadcrumbs

Making a Website Understandable

People must be able to understand the information as well as the operation of the user interface. The content or operation cannot be beyond their understanding. According to the WCAG this includes items such as:

  • Making text content readable and understandable
  • Using menus and and navigation in a consistent manner
  • Helping users avoid and correct mistakes
  • Labeling elements and giving instructions

Making a Website Robust

People must be able to access the content as technologies advance. According to the WCAG this includes items such as:

  • Having no major coding errors
  • Ensuring as technologies and user agents evolve, your content is accessible