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No Accessibility without Usability?

David SloanDigital Media Access Group

University of Dundee

digital media access group

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Accessibility without usability is like……a wheelchair ramp into a library where

books are sorted by size. (and how steep is the ramp anyway?)

• But very easy to get fixated on chasing ‘Bobby compliance’

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Accessibility without Usability?

• Automatically generated Text-only sites– Hand coded Text only sites!

• Bobby approved…but 108 links on the Home page and no easy way to navigate through them

• Alternative text – see example….

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but a blind person might hear…

“Link – Students & graduates”“Link – Youth Accounts”“Man standing on his head”“Link: Internet Banking Login”“Link: Bank of Scotland Information”

…’accessible’ but usable?

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Usability defined

• Ease of learning• Speed of task completion• Low error rate• Retention of knowledge over time• User satisfaction

Ben Shneiderman (1992)

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Legislation

• Section 508 specifically addresses web accessibility

• But legislation not prescriptive for web designers in many countries:– “…or provide a less favourable service” (UK’s

Disability Discrimination Act)• Difficult to equate this to a WCAG priority – so

could this mean the UK’s DDA requires sites to be usable by disabled people?

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Usability for disabled users: examples

• Search facilities– Easy to find on every page– Logical design– Go button last in the tab order

• An accessibility statement that tells disabled users what you’ve done for them…and what you haven’t

• Intelligibility of information in audio– “eResources” spoken as “error sources”

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Know your end users

• What technologies/knowledge can you be confident they will have?

• Involve disabled users in evaluation and testing• Find out what they tolerate...• and what irritates them

– WCAG Checkpoint 10.5: ”Until user agents…render adjacent links distinctly, include non-link, printable characters (surrounded by spaces) between adjacent links”

• But be aware of designing for one user’s idiosyncrasies: all blind people are not the same!

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Summary

• Usability is nothing without accessibility• But accessibility without usability is nothing

either

“Disabled users don’t want accessibility, they want to shop at E-bay, rip off MP3s, pass their

Accounting 101 course…”