Website Navigation for Blind Users

Hans Hillen and Dr. Vanessa Evers, University of Amsterdam

Abstract In this case study Mr. Hillen and Dr. Evers focus on the problems that blind people can encounter when they try to navigate a website. Having investigated these problems they propose some possible solutions which are embedded in a prototype, NavAccess, that was developed and evaluated to address three types of issues that the authors refer to as ‘‘focus challenges’’. These are: providing guidance for blind users; empowering blind users; and reducing cognitive load.

Research goal and approach The goal of this research was to create a prototype, known as NavAccess, that would make navigation of websites more effective, efficient and pleasant for blind users.

So far, the solutions that have been provided to improve website navigation for blind users mostly focus on one specific page. Little has been done to provide solutions that apply to a website as a whole. The goal of this research was to provide such a solution. In order to achieve this goal a prototype, NavAccess, was developed and then evaluated during user sessions with blind participants.

Prototype description The prototype used for this study consisted of a server-based agent that crawled through all pages within a given website, followed each link it encountered (but only those pointing to a page within the current site domain) and collected information about these links and the pages they led to.

As a primary resource, previous studies were used in which the development and evaluation of similar web navigation improvement tools for blind Internet users were described. Secondly, the User Agent Accessibility Guidelines (UAAG) 1.0, developed by the W3C Web Accessibility Initiative,

Interaction Design: Beyond human-computer interaction Sharp, Rogers and Preece ? 2007 John Wiley & Sons, Ltd ISBN-13: 978-0-470-01866-8

2 Website Navigation for Blind Users

were used as a baseline for the interface accessibility requirements. The Web Content Accessibility Guidelines (WCAG) 1.0 were also observed, although the actual content of the NavAccess tool was limited to simple strings of text.

Finally, news groups frequently used by blind Internet users were observed, as well as accessibility web forums such as http://www.accessifyforum.com/. With these guidelines, the first prototype was developed.

The result was a complete record of the ‘infrastructure’ of the given website, which was then communicated to the user interface using XML. This information was then available at the interface to help the user navigate the site (see Figure 1 for example), which could be done using only one hand, through buttons on a numeric keypad. Using the arrow keys the user could move back and forth through the website’s link structure, probing the targets of encountered links without actually following them.

Figure 1 Screenshot of NavAccess prototype Interface

This approach resulted in the user having access to two different styles of navigation:

1. Navigating the site’s structure through the prototype’s interface. This form of navigation has a low level of detail but allows the user to move around the website in a fast and efficient manner, making it possible to have a ‘macro level overview’ of the website as a whole.

Testing the two different navigation styles 3

2. Navigating a specific page through the standard browser interface. When a page of interest was encountered in the prototype macro level overview, the user would be able to switch to the main browser and access the page. This form of navigation is slower than the first navigation style but it offers a higher level of detail, allowing a more detailed analysis of the specific page.

As addition to the main NavAccess functionality described above, several peripheral functions were added:

— Because the target pages had already been parsed on the prototype’s server, the user could request audio ‘preview information’ about the content of the page the link lead to, whether a link was working, whether it resulted in leaving the current domain, whether it was a different protocol than HTTP (such as FTP or mailto), or whether it was pointing to a file that was not a web page (such as an image or a PDF file). Another example of preview information is the use of ‘link title alternatives’ which the user could request to hear the actual title of the target page rather than the actual link phrase, which can be context dependent or even graphical.

— For each link the system checked how many times the link occurred on the site compared to the total number of pages within the website. If a link occurred on more than 80 percent of the pages, it would be identified as a ‘main link’, and made available through separate interface controls. This way the user would always have important links such as ‘home’ available, regardless of whether such a link was present and focused on the currently selected page.

— Context dependent links such as ‘click ‘‘here’’ to visit our website’, (where the actual link phrase is only ‘‘here’’) are difficult to understand when viewed in a different environment (e.g. a screen reader’s link list). The prototype allowed users to extract the textual environment of a link.

The best way to examine the efficacy of this approach was through user testing these two different styles of navigation.

Testing the two different navigation styles User sessions were conducted with ten blind participants to test the navigation styles. Each session consisted of the following phases:

1. A semi-structured interview, in which the participants were asked about the way their impairment influenced their daily lives, the role the Internet played in their daily lives and the problems they experienced when accessing websites.

2. An observation session, where participants were asked to visit a website they frequently visit and carry out tasks tasks they normally carry out on this website while being observed by the

4 Website Navigation for Blind Users

experimenter. This way, more knowledge could be obtained about which problems blind Internet users encounter, and the ways in which they work around these problems, before they tested the prototype.

3. Finally, the participants were asked to explore a website (www.danbrown.com) using the Navaccess prototype, and think aloud while doing so.

The blind participants were given an introduction to the system, in which the main functionalities of the NavAccess interface were described and explained. After the introduction, the participants were allowed five minutes to freely explore the interface. During this phase, the experimenter read out the main functions and key combinations whenever requested, as a help option would. This approach was chosen because the actual NavAccess help content had not been implemented yet in this early prototype, and also to collect feedback about how often users needed to refer to the help when using the system. After this ‘try-out’ phase, the site model of an earlier website accessed by NavAccess (http://www.danbrown.com) was loaded into NavAccess as a datasource. The participants were asked to navigate the structure of this site model using the NavAccess controls. Initially, this second phase required the participants to perform specific tasks in this website structure (e.g. ‘‘navigate to the page where you can order the book ‘the Da Vinci Code’’ ’). However, a pilot with two users made it clear that structured tasks were too cumbersome. Because blind users have to remember the controls, do not have constant visual feedback of options available and it takes time to learn, the decision was made to observe the participants’ experience of using the NavAccess main controls and functions while freely navigating the Dan Brown website. The instructions that they were give were: ‘please explore this website while using NavAccess’.

In phase three the participants were asked to carry out a task they are familiar with on the Internet while using the NavAccess interface. The participant was asked to think out loud. Participants chose their own website and set their own task. Data collected by the researchers included: the age of the participant, visual capabilities of the participant, the accessibility aids used by the participant, Internet and computer experience, how the participant had learned to use the Internet, what he/she uses the internet for, the website accessed in the session, the nature of the task, the duration of the task, the think aloud protocol, and the user log of the session.

Because of the small number of participants in this study, the evaluation results were qualitative data. An example of results for a participant is as follows.

Participant 6 Profile: A 55-year-old male who had been completely blind for 33 years. He used JAWS software as a Windows screen reader. The participant had learned to use the Internet in a DOS environment, mostly for activities such as email and visiting ‘De Digitale Stad’ (the digital city Amsterdam, DDS), a virtual community where people can navigate through a virtual representation of a city, communicate

Testing the two different navigation styles 5

with other citizens and add local content. The participant mentioned that this community was ideal for a blind person because every visitor had to use their imagination, thereby removing the difference between blind and sighted users. The participant mentioned that he does not try to find out how a page’s layout is designed, unless this information is necessary to reach a certain location on a page. In this case the participant asks for help from a sighted person. The participant also mentioned that he encourages the use of frames (whereas frames are often mentioned as an accessibility obstacle) because they allowed him to skip inaccessible content. An example of a task completed in this part of the evaluation is:

The assignment requires a 4-6 page review,not including the cover page,abstract,and a reference page,of the business use case attached.
Answer the following questions:

Summarize the case study
Identify the study method used and why it was appropriate
Explore some of the qualitative or quantitative methods gathered.
Answer these two additional questions:
How would you conduct the study any differently?
Given the nature of the advance of technology, how do you foresee technology changing the way studies such as these are conducted in the future?