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WCAG2 Guidelines and Cognitive Impairment a11y ldn 2011


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A collection of some of the WCAG2.0 accessibility guidelines that relate to those with cognitive impairments. Note: this is a selection - not a full list.

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WCAG2 Guidelines and Cognitive Impairment a11y ldn 2011

  1. 1. WCAG 2.0 Guidelines and Cognitive Impairment<br />Graham Armfield<br />
  2. 2. WCAG 2.0 and cognitive impairment<br />Graham Armfield<br />Who am I?<br />Web developer <br />Accessibility consultant<br />Accessibility tester<br />Fix the Web partner<br />
  3. 3. What this presentation will cover<br />A selection of the WCAG2.0 success criteria and how they relate to those who suffer from cognitive impairments. <br />This is not the full selection<br />Note that I’ve grouped the success criteria by subject rather than by numerical order or priority<br />Also note that I’ve paraphrased success criteria text<br />The numbering on each slide refers to the WCAG success criteria number<br />The priority level is also shown<br />
  4. 4. What this presentation will cover<br />Timed events<br />Audio<br />Handling focus and input<br />Signposting structure and location<br />Signposting destinations<br />Words and meaning<br />Handling errors<br />
  5. 5. For each time limit that is set by the content, at least one of the following is true: <br />It can be turned off<br />Time limit can be adjusted<br />User is warned before time limit expires<br />The time limit is part of a real time event – eg auction<br />The time limit is essential – extending it would invalidate activity<br />Why? <br />Helps ensure that users can complete tasks without unexpected changes in content<br />See also…<br />2.2.1 Timing Adjustable Level A<br />
  6. 6. Timing is not an essential part of the event or activity presented by the content, except for non-interactive synchronized media and real-time events. <br />Effectively - no time limit at all.<br />2.2.3 Timing Level AAA<br />
  7. 7. If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level. <br />Why?<br />Audio can be distracting<br />Separate volume control so as not to interfere with any other audio aids the person may be using<br />1.4.2 Audio Control Level A<br />
  8. 8. Moving, blinking, scrolling, Auto-updating: must allow the user to pause, stop, or hide it or to control the frequency of the update unless it is essential.<br />Why?<br /><ul><li>These can all cause distractions</li></ul>Banner ads can make pages unusable to some people<br />2.2.2 Pause, Stop, Hide Level A<br />
  9. 9. Elements on a page receive focus in an order that preserves meaning and operability.<br />Why?<br /><ul><li>Non-logical sequence can be confusing
  10. 10. Can seriously impact effectiveness of page</li></ul>Some argue that tab order should follow visible screen order – whereas some favour content first.<br />2.4.3 Focus Order Level A<br />
  11. 11. Any element on a page that can receive keyboard focus should overtly indicate that it has focus.<br />Eg. Links, form input elements, buttons<br />Why?<br />Aids understanding of page<br />Helps users orientate themselves within the page.<br />I would also include hover state in that too. Just an underline may not be enough for some – and may be too close to text.<br />2.4.7 Focus Visible Level AA<br />
  12. 12. When any component on a page receives focus, it does not initiate a change of content or context.<br />Why?<br />Unexpected changes are confusing<br />3.2.1 On Focus Level A<br />
  13. 13. Changing the setting of any component on a page does not automatically cause a change of context unless the user has been advised of the behaviour before using the component.<br />Eg. <br />Checkboxes or radio buttons that hide and show panels of text<br />Dropdown box used as navigation<br />Why?<br />Distraction<br />Can cause confusion<br />3.2.2 On Input Level A<br />
  14. 14. Headings and labels describe topic or purpose.<br />ie. Signposting blocks of content<br />Why?<br />Aids understanding<br />Helps break up content into manageable chunks<br />2.4.6 Headings and Labels Level AA<br />
  15. 15. Navigational mechanisms that are repeated on multiple pages within a site or application occur in the same place and same relative order each time they are repeated, unless a change is initiated by the user.<br />Why?<br />Aids orientation in page and site<br />Prevents distracting changes<br />3.2.3 Consistent Navigation Level AA<br />
  16. 16. Information about the user's location within a set of Web pages (website) is available.<br />Eg. Breadcrumb trail, or indicators within navigation<br />Why?<br />Helps users orientate themselves<br />2.4.8 Location Level AAA<br />
  17. 17. The purpose of each link can be determined from the link text alone, or from the link text together with the context of the link.<br />Click here to download document<br />Why?<br />Avoids issue of users arriving in unexpected locations or triggering functionality they didn’t mean to<br />But see also…<br />2.4.4 Link Purpose (in Context) Level A<br />
  18. 18. The purpose of each link can be determined from the link text alone.<br />Click here to download document<br />Why?<br />Avoids issue of users arriving in unexpected locations or triggering functionality they didn’t mean to<br />2.4.9 Link Purpose (Link Only) Level AAA<br />
  19. 19. When text requires reading ability more advanced than the lower secondary education level, an alternate version that does not require such a high reading ability is available.<br />Could be alternate pages, or show simple summaries by default and show advanced content with scripting.<br />Why?<br />Caters for those with learning difficulties or with linguistic comprehension impairment<br />3.1.5 Reading Level Level AAA<br />
  20. 20. A mechanism is available for identifying specific definitions of words or phrases used in an unusual way, including jargon.<br />Why?<br />Avoids confusion<br />3.1.3 Unusual Words Level AAA<br />
  21. 21. A mechanism for identifying the expanded form or meaning of abbreviations is available.<br />Why?<br />Avoids confusion<br />3.1.4 Abbreviations Level AAA<br />
  22. 22. Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality.<br />Why?<br />Larger text aids legibility<br />Note: Enlarging text is not the same as zooming in – difference between Chrome and Firefox/IE<br />Ideally enlarging text should not break page design<br />1.4.4 Enhanced Text Level AA<br />
  23. 23. Ensure sufficient contrast between text colour and background colour.<br />Why?<br />Better contrast ensures easier legibility<br />Note: Text that is part of a logo or brand name has no minimum contrast requirement.<br />But, some find too much contrast leads to difficulties too<br />1.4.3 Contrast (Minimum) Level AA<br />1.4.6 Contrast (Enhanced) Level AAA<br />
  24. 24. If an input error is automatically detected, the item that is in error is identified and the error is described to the user in text.<br />ie. Not just change of colour or appearance of icon<br />Why?<br />Users understand why unexpected things have happened<br />Note: use of colour and/or icons to indicate errors is a useful mechanism but it should not be the only mechanism.<br />3.3.1 Error Identification Level A<br />
  25. 25. If an input error is detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardize security.<br />Why?<br />Users are not put off by unexplained issues<br />3.3.3 Error Suggestion Level AA<br />
  26. 26. I hope it’s been useful<br />Any questions?<br />