Different Standards for Different Purposes
Tutorial Page 5
Although accessibility is related to the issues of usability and coding standards, it is possible for a site to be considered usable and standards compliant but NOT accessible (and vice-versa). Below are some definitions, and situations where distinctions may arise.
Usability
Usability refers to the ability of average users with the “standard” range of equipment or perceptual and motor abilities to navigate and use a Web site. In most cases, accessibility standards will also add usability to a Web site, but accessibility consists of more than just general usability.
Having said that, many people do feel that accessibility is an important component for ensuring that content is truly usable for all audiences. On the flip side, adding accessibility features (e.g. captions, table captions and headers) enhances accessibility for all users beyond those requiring these features.
Web Standards
Web standards refer to an initiative from the W3C and other Internet standards bodies to develop open Web standards that can be used by any software
developer. The goals of such standards are to ensure cross-platform compatibility and more compact file sizes.
The focus of these standards has been to separate “content” from “formatting” by implementing CSS. Although CSS can definitely facilitate accessibility, it is possible to design inaccessible styles. Similarly, a non-CSS solution could be as equally accessible as a CSS solution.
A standards-compliant site does not guarantee an accessible site.
Potential Mismatches
Although many accessibility guidelines are straightforward, in some cases guidelines may conflict with usability or standards. For these cases, extra care must be taken to ensure that all audiences are able to access and use a Web site.
| Issue | Good Usability/Standards | Bad Accessibility | Solution |
|---|---|---|---|
| Color Coding | Color is a key visual signaling device for humans. | About 10% of men are partially color blind and cannot distinguish certain colors (especially red/green). |
Supplement color-coding with text/icon coding. |
| Multimedia | Using images, sound and animations can often be more comprehensible than large blocks of text. Some people even recommend icons for users with cognitive impairments. |
Screen readers cannot interpret multimedia elements without textual assistance |
Always implement ALT text, extended text descriptions and/or captioning or transcripts |
| Repetitive Navigation | Having navigation buttons repeated on top and bottom is good for consistency and for those with some motion disorders. |
It may be tedious for screen reader users to hear the navigation on every page. |
Implement a “skip navigation” strategy. |
| Multiple Columns | Multiple columns are one way to reduce text width, which is conducive to legibility, and allows more material to fit in one screen. |
Multiple columns are difficult for some screen readers to interpret. | Use style sheets to reduce a column width within a single-column layout. Use appropriate table tags for data tables, and make sure layout tables make sense when read left to right, top to bottom. |
| Unicode for Foreign Languages | Unicode makes data exchange between operating systems and foreign languages easier. |
Some screen readers cannot recognize Unicode input. | Consider how screen readers can access foreign language content. |
| PDF Files | PDF files may be the only way to present some types of information. | Screen readers may not be able to interpret all the information. | PDF files need to be made accessible or content must be provided in alternative format. |