Link annotation with the accessibility level of the target Web page is an adaptive navigation support technique aimed at increasing blind users’ orientation in Web sites. In this work, the accessibility level of a page is measured by exploiting data from evaluation reports produced by two automatic assessment tools. These tools support evaluation of accessibility and usability guideline-sets. As a result, links are annotated with a score that indicates the conformance of the target Web page to blind user accessibility and usability guidelines. A user test with 16 users was conducted in order to observe the strategies they followed when links were annotated with these scores. With annotated links, the navigation paradigm changed from sequential to browsing randomly through the subset of those links with high scores. Even if there was not a general agreement on the correspondence between scores and user perception of accessibility, users found annotations helpful when browsing through links related to a given topic.

1. Enriching Web Information Scent for Blind Users Markel Vigo1, Barbara Leporini2, and Fabio Paternò2 1 Laboratory of HCI for Special Needs 2 Human Interfaces in Information Systems 1 University of the Basque Country 2 Italian National Research Council

2. Hypothesis: annotating links with the accessibility level of the page where they point would increase user orientation “Visually impaired users need to be warned of obstacles because their reliance on cues is higher than for sighted users”- Goble et al. ”Detecting and notifying users about barriers improves user orientation”- Harper et al. Goal: use of accessibility assessment results in web navigation scenarios Information Scent: Thus, we aim at enriching information scent using accessibility assessment results for screen reader users. 1. Introduction 1. Visual or textual cues provided on a Web site to suggest what information its links may contain. 2. The perceived usefulness of a page based on such information. Enriching Web Information Scent for Blind Users ACM ASSETS2009

3. Hypothesis: annotating links with the accessibility level of the page that the link point to increases user orientation “Visually impaired users need to be warned of obstacles because their reliance on cues is higher than for sighted users”- Goble et al. ”Detecting and notifying users about barriers improves user orientation”- Harper et al. Goal: deployment of accessibility assessment results in navigation scenarios Information Scent: Thus, we aim at enriching information scent using accessibility assessment results 1. Introduction not accessible highly accessible 1. Visual or textual cues provided on a Web site to suggest what information it or its links may contain. 2. The perceived usefulness of a page based on such information. fairly accessible Enriching Web Information Scent for Blind Users ACM ASSETS2009

7. 4 principles: structure and arrangement, content appropriateness, multimodal output, consistency

8. automatic guideline review tool: Magenta

9. Magenta checks adequate content of tags and attributes, arrangement of headings or shortcutsEnriching Web Information Scent for Blind Users ACM ASSETS2009

11. Addressed

12. Addressed but not implemented- Complementary - Contradictory Enriching Web Information Scent for Blind Users ACM ASSETS2009

14. Using aggregation methods

15. Considering issue typology:

16. automatic issues (earl:automatic) yield earl:passed or earl:fail

17. recommendations

18. semi-automatic issues (earl:semiAuto)Enriching Web Information Scent for Blind Users ACM ASSETS2009

19. 3. User-Tailored Assessment: Measurement Traditional aggregation: where W: weights and E: evaluation results Logic Scores Preferences: where ρ(d) are values selected upon the required logical relationship between evaluation results. d=0 conjunction 0< d <0.5 quasiconjunction: simultaneity in satisfying all the evaluations d=0.5  arithmetic mean 0.5< d <1 quasidisjunction: penalizes only when all evaluations are not satisfied d=1 disjunction Only intermediate values are applied Enriching Web Information Scent for Blind Users ACM ASSETS2009

21. between guidelines, mean valuefinal score ? guidelines 0.25 checkpoints test cases T2 T3 T1 1 0.25 0 Enriching Web Information Scent for Blind Users ACM ASSETS2009

23. Experimental settings

24. 16 experienced blind users. Age M=43, sd=11

25. JAWS on Internet Explorer

27. Browsing by navigating

28. Searching by navigatingEnriching Web Information Scent for Blind Users ACM ASSETS2009

30. Goal: observe users with no/vague target in mind

31. Two sites with 10 links

32. Top ten search results for “Pisa” and “Firenze” keywords

33. Results were heterogeneous links wrt topic,

34. Following a pattern: wikipedia, local university, soccer team and so on

35. One site was manually annotated with accessibility scores and relevance scores

36. Relevance based on ranking {very relevant, relevant, medium, low, irrelevant}- 5 min free browsing. They had to write a report about what they learned Enriching Web Information Scent for Blind Users ACM ASSETS2009

38. 9 users proceeded sequentially. Kendall τ=[0.8-1.0] at most p<0.03

39. In the page with annotations,

40. Only 2 users proceeded sequentially. Kendall τ=1.0 at most p<0.05

41. None followed the sequence of most accessible links

42. None followed the path based on relevance

43. Some proceeded dichotomously

44. However, when aggregating accessibility scores of visited pages, 7 points over the median are obtained

45. This, can be interpreted as if the users browsed within the subset of more accessible pages according to random/preference criteriaEnriching Web Information Scent for Blind Users ACM ASSETS2009

47. Goal: observe users with a specific target in mind

48. Two sites with 10 links

49. Top ten search results for “Accommodations in Pisa”

50. Results were homogeneous links wrt topic

51. One site was manually annotated with accessibility scores

52. Relevance was not considered

53. Two tasks: (1) given a telephone number (2) address

54. They had to write down the name of the hotelEnriching Web Information Scent for Blind Users ACM ASSETS2009

56. Only 2 users proceeded sequentially. Kendall τ=1.0 at most p<0.05

57. One user proceeded inversely. Kendal τ=-1.0 at most p<0.02

58. In the page with annotations,

59. Only 2 users proceeded sequentially. Kendall τ=1.0 at most p<0.05

60. One user followed the most accessible path. Kendal τ=1.0 at most p<0.02

61. Again, when aggregating accessibility scores of visited pages 6 points over the median are obtainedEnriching Web Information Scent for Blind Users ACM ASSETS2009

64. “scores are useful”, “scores are interesting”

65. “accessibility scores seem correct”

68. “scores don’t convey the actual difference in accessibility level” “scores make navigation smoother and more instinctive”

69. “scores seem random””I missed accessibility scores in this task” Enriching Web Information Scent for Blind Users ACM ASSETS2009

71. “Scores are useful for the browsing task”

72. “Scores are useful for the searching task”

73. “Scores are correlated with actual accessibility level in browsing task”

74. “Scores are correlated with actual accessibility level in searching task”Enriching Web Information Scent for Blind Users ACM ASSETS2009

76. Although there is not an agreement

77. “The perception of accessibility depends on each user and their particular computer settings”

78. There is no agreement on the type of scores they prefer

79. 50% for qualitative and quantitative

80. Considering the informal comments it seems that the annotation technique prevails over scoresEnriching Web Information Scent for Blind Users ACM ASSETS2009

82. In the browsing scenario users change paradigm

83. From sequential browsing to random in the subset of most accessible links

84. Subjective scores are more balanced than in the searching scenario

85. When directly enquired, users state that accessibility annotations would be useful in those scenarios where the topic of the linked pages would be similarEnriching Web Information Scent for Blind Users

87. Enriching Web Information Scent for Blind Users Questions? Markel Vigo1, Barbara Leporini2, and Fabio Paternò2 1 Laboratory of HCI for Special Needs 2 Human Interfaces in Information Systems 1 University of the Basque Country 2 Italian National Research Council