Jeffrey P. Bigham Anna C. Cavender, Jeremy T. Brudvik, Jacob O. Wobbrock * and Richard E. Ladner Computer Science & Engineering The Information School* University of Washington A Comparison of Blind and Sighted Browsing Behavior

Study Overview Proxy-based observation for one week 10 Blind and 10 Sighted (Ages 18-63) Either Internet Explorer or Firefox Blind participants used JAWS 21,442 Pages 4,204,904 Events Introduction Geographic Diversity of Users

in situ Study Introduction Valuable Qualities  Participants use their own tools  Familiar, preferred web pages  Observe longer time periods Usage Patterns in Usual Browsing  Effects of web accessibility  Coping strategies employed  Differences in content chosen to view

Important Complement to Prior Work DetailResearcher Observation Standard Tasks User’s Tools Longer Times Lab 1,2 Field 3 Diary 4 WebinSitu [1] Takagi et al. Analysis of navigability of Web applications for improving blind usability [2] Watanabe et al. Experimental evaluation of usability and accessibility of heading elements [4] Coyne et al. Beyond alt text: Making the web easy to use for users with disabilities [3] Lazar et al. Determining the impact of computer frustration on the mood of blind users Introduction

Outline Introduction Experimental Setup and Study Design Browsing Differences Effects of Content

A Proxy-Based System Used UsaProxy 1 [1] Richard Atterer et al. Knowing the User's Every Move - User Activity Tracking for Website Usability Evaluation and Implicit Interaction. WWW 2007 Setup and Study Design

More than a regular proxy Setup and Study Design GET 10 Oct :12:30http://webinsight.cs.washington.edu/ GET 10 Oct :12:30http://webinsight.cs.washington.edu/pics/web-eye.gif GET 10 Oct :12:31http://webinsight.cs.washington.edu/css/style.css … Keypress, ctrl f, 10 Oct :12:35 Mouse, 540x232, 10 Oct :12:36 Focus, Text Box (name), 10 Oct :12:36 AJAX, url=“ 10 Oct :12:36 Page Changed, 10 Oct :12:39 … Image, alt=“Contact Us”, src=“ Link, name=“University of Washington”, url=“ … Requests Actions Content

Easy Setup and Deployment Setup and Study Design No New Software to Install Works with Existing Tools

Outline Background Experimental Setup and Study Design Browsing Behavior Effects of Content

Using the Mouse Blind Users Don’t Use a Mouse  but, sometimes they have to BlindSighted Pages with Mouse Movements 25.9% (n.s.) 35.1% Avg. Discrete Movements per Page 0.43 (p < ) 8.21 % of Pages with Mouse Movements per Participant Browsing Differences

Using the Mouse (why) “…if there's a command in a form or shopping cart that says, ‘click here,’ with no labeled button, I must route my cursor to that position…” Browsing Differences

Probing: technical papers technical program Call for Papers Technical Program Browsing Differences Following a link and returning in less than 30 seconds

Blind1 out of 3 pages Sighted1 out of 8 pages Web Pages with Probes Browsing Differences (p < 0.01)

Browsing Efficiency Blind Users Less Efficient Overall, ~2x longer per page  Contrast to 10x on completing tasks 1 Why not more?  Web pages, not tasks  Accustomed to Web Pages  “errors” (including probing) [1] Takagi et al. Analysis of navigability of Web applications for improving blind usability Browsing Differences (p < 0.1)

Using Google Browsing Differences TaskBlindSighted Entering Query 74.6 sec. (p < 0.01) 34.5 sec. Selecting Result sec. (p < ) 34.8 sec.

Outline Background Experimental Setup and Study Design Browsing Differences Effects of Content

Images and Alternative Text (empty) proceed.gif pubbank-button.gif s.gif Blind Users are Smart Effects of Content

Images and Appropriate Alt. Text % of Images with App. Alt. Text  Did not influence browsing behavior Influenced Clicking Behavior: BlindSighted 72.2%34.0% Clicked Images with App. Alt. Text % of Images Assigned Appropriate Alternative Text on Visited Pages Effects of Content (p < 0.01)

Skip Links “Skip top navigation and go to home page content” 822 Skip Links Blind users clicked 5.6% “Skip links are almost always broken.” Effects of Content

Dynamic Content  15.0x fewer pages viewed (p < 0.07)  19.3x fewer interactions with dynamic content (p < 0.01) AJAX  7.5x fewer (p < 0.05) Flash  44.1% were ads  Blind participants used for sound content  Only 5.6% were main content Effects of Content

Summary and Future Work Main Points  Facilitated new type of study  Confirmed anecdotal observations  Interesting new directions Many Remaining Questions  Efficiency and experience  Content requires using the mouse  Annotation of dynamic content (ARIA)  Extent of Flash accessibility  MANY OTHERS Effects of Content

WebInSight webinsight.cs.washington.edu Thanks to: National Science Foundation Max Aller, Richard Atterer, Darren Gergle, Steve Gribble, Sangyun Hahn, Scott Rose, Lindsay Yazzolino. The End

Important Complement to Prior Work Detail Voice Output No User Recording Standard Tasks User’s Tools Longer Times Lab 1,2 Diary 3 Field 4 WebinSitu [1] Takagi et al. Analysis of navigability of Web applications for improving blind usability [2] Watanabe et al. Experimental evaluation of usability and accessibility of heading elements [3] Lazar et al. Determining the impact of computer frustration on the mood of blind users [4] Coyne et al. Beyond alt text: Making the web easy to use for users with disabilities Background and Motivation