Accessibility, Usability and Standards - What Does it Mean?

Published: 21 November, 2002

With all the buzzwords flying around this industry it's a wonder anyone can keep up but in amongst it all are some words that warrant well defined use. These are the concepts of accessibility, usability and web standards. All three are vitally important to the success of web based content but often get fired around as if they were marketing terms and as such have started losing their impact. In this article we'll have a look at the difference between the three concepts and what they mean to people working with the web.

Accessibility

The primary focus of Web accessibility is to make content available to people with disabilities. The secondary focus is to make content accessible regardless of the user agent (ie. device) being used to access that content.

Accessibility is by no means unique to the Web (think building access, public toilets etc) but certainly seems to cause the most confusion possibly due to the wide range of people developing for and using the Internet. The principles are much the same as in other industries but the means are obviously different. The World Wide Web Consortium (W3C) manages the Web Accessibility Initiative (WAI) which contains guidelines for creating accessible content on the Web. Common accessibility techniques already in use include the use of alt text on images, well structured content through good use of HTML and effective use of colour (eg. good contrast).

Creating accessible web sites not only benefits people with disabilities but the techniques usually make content more accessible, and often more usable, for everyone. It is simply good practise to create Web based content that is easy to access.

Usability

"Usability addresses the relationship between tools and their users. In order for a tool to be effective, it must allow intended users to accomplish their tasks in the best way possible" (Usability First).

Designers focused on creating tools (including web sites and applications) so they adhere to usability principles tend to look at the following concepts:

  • Ease of learning: How fast can a user who has never seen the user interface before learn it sufficiently well to accomplish basic tasks?
  • Efficiency: Once an experienced user has learned to use the system, how fast can he or she accomplish tasks?
  • Memorability: If a user has used the system before, can he or she remember enough to use it effectively the next time or does the user have to start over again learning everything?
  • Error frequency and severity: How often do users make errors while using the system, how serious are these errors, and how do users recover from these errors?
  • Subjective satisfaction: How much does the user like using the system?

Usability is similar to accessibility in that it is not unique to the Web or software development but is recognised as a general design principle.

Standards

The term web standards describes technologies established by the World Wide Web Consortium (W3C), along with other groups and standards bodies, for creating and interpreting web-based content. Like all standards they are methods and recommendations that are agreed upon and used by those involved in the industry.

The most commonly recognised standard in use on the Web at this stage is HTML which is the major markup language used to deliver content. Other specifications that are fast entering the mainstream in terms of their increased use include:

  • XHTML: Extensible Hyper Text Markup Language
  • CSS: Cascading Style Sheets
  • XML: Extensible Markup Language
  • XSL: Extensible Stylesheet Language
  • DOM: Document Object Model
  • SVG: Scalable Vector Graphics

Summary

Accessibility, Usability and Standards compliance are all things that work together to make up a solid web solution, whatever it's purpose may be, and are all worth pursuing. The Internet is still in it's very early stages and there are certainly restrictions but it is now practical and worthwhile to start creating standards compliant web content that is accessible and makes it easy for people to find and work with.