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W4A2013 - Web Accessibility Snapshot: An Effort to Reveal Coding Guidelines Conformance


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Work presented during the W4A 2013.

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W4A2013 - Web Accessibility Snapshot: An Effort to Reveal Coding Guidelines Conformance

  1. 1. © 2013 IBM CorporationWeb Accessibility Snapshot:An Effort to Reveal Coding GuidelinesConformanceVagner Figueredo de Santana and Rogério Abreu de PaulaIBM Research Brazil, Social Enterprise Technology Group, Service SystemsMay 13, 2013IBM Research
  2. 2. © 2013 IBM CorporationAgenda Introduction and background Motivation Approach Results Discussion and conclusion
  3. 3. © 2013 IBM CorporationIntroduction and backgroundThe Web has at least 14 billions of pages (
  4. 4. © 2013 IBM CorporationIntroduction and background World Health Organization says that 15% have some for of disability Web Accessibility– Perceive– Understand– Navigate– Interact– Contribute Correct Web pages markup is essential to semantics
  5. 5. © 2013 IBM CorporationIntroduction and background Level of comprehension required to understand the guidelines might bethe cause of its low use by web developers– Sloat et al.2006 Automated tests count on 35% of false negatives– Brajnik, 2004 Guidelines are not the “silver bullet” for Web accessibility Coding guidelines set the minimum standards Conformance with coding guidelines is not sufficient … but it is necessary
  6. 6. © 2013 IBM CorporationMotivation Inspiration: Nomensas report to the United Nation The Nomensas report:– Run in 2006– Counted on 100 websites– Involved sites from 20 countries– Results: 97% of the websites did not reach WCAG 1.0 (Level A) Objective:– To draw a broader and updated picture of coding guidelinesconformance– Considering• The top 1,000 popular websites• Sample of 1,000 websites
  7. 7. © 2013 IBM CorporationApproach To provide a snapshot– Alexa.coms top 1,000 popular websites (homepages)– Sample of 1,000 websites (homepages) To automatically evaluate– Selenium IDE•– AChecker• Metrics considered– WCAG 2.0 Level A• Minimum level to which a Web page should conform– Known problems reported by AChecker• Identified with certainty as accessibility barriers• Developers must fix these problems
  8. 8. © 2013 IBM CorporationApproach Sampling the Web– Input• One alphanumeric array (a, b, c, …, 0, …, 9)• One array containing top level domains (ac, ad, …, com, …, net, …)• List size (e.g., 1000)– Procedure• While the lists length is less then 1000– Generates the length of the host name– While host name is less than the generate lengthSelect a random position and concatenates it to the host name– Selects a random top level domain and concatenates it to the host– Tries to connect to the generated address– If the address is valid, then it is added to the list of addresses– Output• List of working addresses
  9. 9. © 2013 IBM CorporationResults Sampled (n=987)- Mean known problems7.00 (SD=35.48)- One or more known problems: 85.11%- Zero know problems: 14.89% Top popular (n=922)- Mean known problems:32.97 (SD=60.47)- One or more known problems: 95.66%- Zero know problems: 4.34%
  10. 10. © 2013 IBM CorporationResults Sampled vs Top 1,000- Results do not follow a normaldistributionShapiro-Wilk → p-value < 0.001- Result sets are differentWilcoxom Rank Sum → p-value 0.001- Popularity is not correlated to thenumber of known problemsPearson correlation coefficient of 0.09
  11. 11. © 2013 IBM CorporationDiscussion and conclusion Homepages with know problems ranges form 85-95%– Why homepages? Conformance is necessary... not sufficient A lot of work is beyond of automatic evaluation.... and this snapshot Commonly found problems– Missing alt attribute– Form with missing labels Web Accessibility Snapshot project aims at– Providing updates in this subject– Invite organizations to solve issues of higher impact with easy fixes– For the future• To increase the data set• To highlight more and more an action-centered point of view
  12. 12. © 2013 IBM CorporationIf you want to know more about the project,just let me know.... you!