Usability and Accessibility

Usability

A usable web site is one that visitors find easy to use. They are able to locate the information they seek quickly and easily. The text is easy to read. They can figure out where they are in the site and how to get back to where they were earlier. They don't have to wait more than a few seconds for a page to download. They can jump from one page to another with one or two clicks; they don't have to repeatedly use the back button.

Following the principles of usability makes the site easier to use for all visitors.

Accessibility

An accessible web site is one that can be used by visitors with particular requirements. There are three classes of requirements that accessibility addresses:

• Physical limitations of the visitor: for example, poor vision, colour blindness, complete blindness, poor motor control.
• Technological limitations of the visitor's computer environment: choice of browser, size of browser window, screen size and screen resolution, speed of internet connection.
• Intellectual limitations of the visitor: children, mentally challenged visitors, visitors who are not comfortable in English, visitors who cannot read easily.

Following the principles of accessibility makes the site easier to use for visitors who have particular requirements.

There are many overlaps between the principles of usability and accessibility, so they are usually treated together. However, if your site is targetted to an audience with particular accessibility requirements, we address those individually.

The Usability menu on the left explains some of the design principles we follow at Usable Web Designs.