Web accessibility has so many benefits that I really do wonder why such a large number of websites have such diabolically bad accessibility. One of the main benefits is increased usability, which according to usability guru, Jakob Nielson, can increase the sales/conversion rate of a website by 100% and traffic by 150%.

At which point you must surely be asking, “So if I make my website accessible its usability will increase and I'll make more money out of it?”. Well, not quite. An accessible website is not automatically more usable but there are many areas of overlap:

1. Descriptive link text

Visually impaired web users can scan web pages by tabbing from link to link and listening to the content of the link text. As such, the link text in an accessible website must always be descriptive of its destination.

Equally, regularly sighted web users don't read web pages word-for-word, but scan them looking for the information they're after.

Link text such as 'Click here' has poor accessibility and usability as both regularly sighted and visually impaired web users scanning

the paragraph will take no meaning from this link text by itself. Link text that effectively describes its destination is far easier to scan and you can understand the destination of the link without having to read its surrounding words.

2. Prompt text assigned to form input

In order to make forms accessible we need to assign the prompt text to its form item. THis is especially useful when done with checkboxes and radioboxes, as the text becomes clickable too. Checkboxes and radioboxes are small and pernickety for even the steadiest of hands so by increasing the clickable region everyone benefits.

3. Large chunks of information divided up

There are a number of techniques that can be taken to increase the usability for visually impaired users, who have to listen to the information on each page and try to remember it. By structuring information into small, manageable groups, enhanced usability for these users can be achieved.

Methods to accomplish this can include using sub-headings to break up body content, grouping form items with the fieldset command and using lists. Breaking down groups of information is obviously highly useful for sighted web users too, as it greatly enhances our ability to scan the screen quickly.

4. Site map provided

Site maps can be a useful accessibility tool for visually impaired users as they provide a straightforward list of links to the main pages on the site, without any of the fluff in between. Site maps are of course useful for everyone as they provide us with a way of finding pages quickly and help us visualise the structure of the website.

5. Simple and easy language

From an accessibility point of view, this one's important for people with reading and/or cognitive disabilities and site visitors who's first language isn't the one you're writing in. From a usability point of view, well, it helps everyone. Reading from computer screens is tiring for the eyes and about 25% slower than reading from paper. As such, the easier the style of writing the easier it is for site visitors to absorb your words of wisdom. Wherever possible shorten your sentences. Use, ‘apply’ instead of ‘make an application’ or ‘use’ instead of ‘make use of’.

6. Consistent navigation

Having consistent navigation across pages is also important for maximising accessibility to people with reading and/or cognitive disabilities, but again everyone benefits. Each time you visit a new website it takes you a few seconds to adjust to the unique layout and user interface of that page. Well imagine if you had to do that every time you follow a link to a new page!

By having a consistent interface across a website we can instantly locate the navigation and page content without having to look around for it. In reality, most sites do have consistent navigation across most pages. The main culprit for falling foul of this guideline is the homepage, which some websites structure quite differently to the rest of the site. By having a consistent interface across the entire website we can instantly locate the page content without having to

About the Author: This article was written by Trenton Moss. He's crazy about web usability and accessibility - so crazy that he went and started his own web usability and accessibility consultancy ( Webcredible - http://www.webcredible.co.uk ) to help make the Internet a better place for everyone.