Principles of Accessibility

The Web Content Advisory Group (WCAG) of the Worldwide Web Consortium (W3C) espouses four basic principles of accessibility:
  • Content should be Perceivable - Information and user interface components must be presentable to users in ways they can perceive.
  • Content should be Operable - User interface components and navigation must be operable.
  • Content should be Understandable - Information and the operation of user interface must be understandable.
  • Content should be Robust - content should be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.
These are used as the basis for the internationally-recognized standards Web Content Accessibility Guidelines (WCAG) published by the Worldwide Web Consortium (W3C).

Designing for Accessibility

Designing for people with disabilities includes:
  • making websites generally easier for all users
  • avoiding non-accessible technologies (or providing technologies)
  • designing for assistive technologies
When designing for accessibility we are trying to make a website for everyone including people with:
  • visual impairments
  • hearing difficulties an impairments
  • neurological disorders (e.g. epilepsy)
  • impaired motor skills/movement

So in general
  • use CSS
  • ensure information that is in non-text format is also in text format
  • make fonts able to be resized
  • enable the web pages to work without scripting, CSS etc
  • make all content accessible by keyboard


Which of the following makes your website more accessible?

  1. Alternative text for images
  2. Lots of graphics
  3. Redundant text links for imaged-based links
  4. Use headings, summaries and captions for tables
  5. Use CSS for formatting
  6. Use HTML rather than PDFs or Flash
  7. Design to work in all major browsers
  8. Use colour to emphasise text
  9. Ensure good colour contrast between text and background
  10. Use captioning and transcripts for audio and video
  11. Use pop-ups

Answer: All except 2 & 11

Case Study

Sydney Organising Committee for the Olympic Games
The Sydney Organizing Committee for the Olympic Games (SOCOG) was required to pay compensation and fix up its website because it was discriminatory.
In 2009 Bruce MacGuire, a blind person made a complaint that the SOCG website did not
  1. have text alternatives (ALT text) for all its images and image map links
  2. enable access from the schedule page to the index of sports
  3. make its tables accessible
In August 2000, the Human Rights and Equal Opportunity Commission (HREOC) upheld the complainant and ordered SOCOG to update their website before the Olympics. On November 6th (after the Olympics), the website was still only partly compliant, so the complainant was ordered $20,000 in compensation. The guidelines used to access the website included the W3C and WCAG 1.0.
The SOCOG website did have images without text alternatives (including an image map). It also included a table which was not able to read properly using a screen reader. SOCOG made the defense that it could not change their page without reasonable hardship. This argument was rejected as the cost was seen as minor, and the guidelines were in place before the website was created - so should have been included in the process (and could have been done so cheaply)
This case set a precedent in Australian law so much that WCAG was set as the standard.

For more information on this case study: A Cautionary Tale of Inaccessibility: Sydney Olympics Website