Analysis of Navigability of Web Applications for Improving Blind Usability Presented by Lindsey Flash April 22, 2008 Written by: Hironobu Takagi, Shin Saito, Kentarou Fukuda, and Chieko Asakawa Published: ACM Transactions on Computer-Human Interaction September 2007

2 Why is This Important? An ever increasing amount of functionality is becoming available on the web An increasing legally blind population Currently 179,000 in Japan Currently 1.3 million in the U.S. Advances in technology and competition have made many sites visually rich Designing more usable web interfaces for everyone

3 Questions Do blind users parse a webpage into subregions when they access a page? How inaccessible are current online shopping sites? How is the regulation for web accessibility contributing to increasing accessible online shopping sites? How are blind users accessing the less accessible sites? What leads to failure?

4 Visual vs. Nonvisual Navigation A short demonstration…

5 Simulating NonVisual Navigation Animals Cat Dog Beagle Retriever Turtle Mouse Bird Parakeet Hawk Fruits Apple Red Delicious Granny Smith Orange Lemon Cherry Lime Grape States Ohio Texas Florida California Maine South Dakota Oklahoma Arizona New Hampshire Colors Blue Navy Blue Sky Blue Green Red Purple Indigo Lilac

6 Visual Navigation Animals Cat Dog Beagle Retriever Turtle Mouse Bird Parakeet Hawk Colors Blue Navy Blue Sky Blue Green Red Purple Indigo Lilac Fruits Apple Red Delicious Granny Smith Orange Lemon Cherry Lime Grape States Ohio Texas Florida California Maine South Dakota Oklahoma Arizona New Hampshire

7 Mental Models of Scanning

8 STUDY 1: Evaluation of Online Shopping Sites’ Navigability Accessibility difficulties Variety of small promotional “tools” Best seller rankings Personalized recommendations Comments from buyers Strong domination of visually oriented business logic Screen real estate Rapid changes of items

9 Nonvisual Navigability Analysis Standard guideline: W3C’s Web Content Accessibility Guidelines (WCAG) “Nonvisual Usability Visualization Method” Analyzes navigability based on graph structures defined by heading tags and skip links Calculates reaching time to each part of a page when using voice browsers An important, and new, contribution of this paper

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11 Measured Criteria 30 online shopping sites evaluated United States 10 Japan10 U.K10 Criteria Reaching times to main content Ratios of pages with heading tags Ratios of pages with skip links

12 Results from Study 1

13 STUDY 2: Experiment on Voice-Access Behavior Experiment 1 Examines the entire process of realistic online shopping Compares completion times between sighted and blind shoppers Experiment 2 Compares users’ behavior on the original pages and accessibility- enhanced pages

14 Experiment 1: Comparison of Shopping Processes between Sighted and Blind Users Subjects asked to buy a DVD for a popular TV program Average completion times: 46.3 seconds for sighted users seconds for blind users Blind participants more than 10 times slower than sighted

15 Experiment 2: Comparison of Original Pages and Accessibility-Enhanced Pages Accessibility enhancements: Alternative texts added for images Skip links added at top of each page Item numbers added to each item Heading tags added to all pages No content removed Ordering unchanged

16 Experiment 2: Comparison of Original Pages and Accessibility-Enhanced Pages No difference in results for reaching times to main content Participants lacked experience in navigating accessible sites Participants spent significantly longer time in the content areas Participants learned various landmarks around the main content in each experimental session

17 Future Work Consideration of a landmark-oriented model for nonvisual navigation Simplification of navigation interfaces Participants mainly used only four commands for navigation in Study 2 Automatic suggestion of navigation methods Integration of transcoding functions

18 Summary Conclusions New regulations regarding accessibility have significantly contributed to better navigability in the U.K. Blind users took more than 10 times longer to locate a specific search item compared with sighted users Landmark-oriented nonvisual navigation model proposed to increase navigability

19 Questions?