Thesis Archive
A study on the factors affecting web site usability for the visually impaired (2009)
Javish H. Abichandani
Kristine F. Gallevo
Jamieson Ivin S. Rabo.
Abstract:
-The growing need of providing convenient access of information in the Web that will not in anyway discriminate people with disabilities particularly those with visual impairments is undeniably significant. The role of the Web, as an edutainment zone and a vast repository of information that connects people worldwide, has frequently been denied to the visually impaired. Although numerous studies on Web usability for the sighted exist, there has not been enough research to establish effective Web navigation for the visually impaired.
Studies done by Theofanos & Redish (2003) and Correani et al. (2004) focused more on constructing Web design guidelines for the visually impaired. However, taking all these elements and their possible variations into account is often far too complex and tedious for determining the true factors that affect Web usability. Tagaki et. al (2007) on the other hand, only obtained a fine-grained analysis of the real behavior of visually impaired users while doing tasks online in which he only considered the scanning navigation of visually impaired users. In spite of these efforts, serious usability issues still exist in many Web pages. This rely on the fact that much of the work did not focus on Web usability factors that should be defined to establish the foremost foundation on understanding aspects on how users with visual impairments deal with Web sites and how such each factor affect their performance online. Thus, points of reference and criteria guidelines should be derived from Web factors.
In addition, Interviews and task observations with users who have visual impairments revealed that a high degree of Web dissatisfaction is present. Visually impaired users encounter problems such as not reaching their desired goal, and often feeling lost and helpless while navigating a Web site which can be really frustrating and time-consuming. In the pursuit of resolving the problems encountered by the visually impaired, a number of accessible guidelines and assistive devices have been developed. Yet, these alone are not enough to cater their needs in achieving their goals online. Researchers and developers should focus on how to improve the usability o the Web site itself.
Bridging the gap between accessibility and usability, this study aims to determine the effect of menu structure, number of links and length of link on Web usability for the visually impaired and the relationship of these important factors for effective Web navigation and performance. Response variables considered were task completion time, number of keystrokes, Post-Study System Usability Questionnaire (PSSUQ) score, and NASA-TLX ratings to evaluate the design’s efficiency, effectiveness, satisfaction and cognitive load give, respectively. The sample consisted of 32 visually impaired users. Data were collected through the use of Web site prototypes and usability testing. Results from testing were validated through the use of Design of Experiment (DOE) and Analysis of Variance (ANOVA). Consequently, a summated usability metric (SUM) was used as tool to integrate aspects of usability to evaluate the overall Web usability.
The result of the study revealed the significant effects of Web usability factors for the visually impaired such as the menu structure, the number of links and the length of link. In addition, the combined effects of these factors were determined. It was found that a relationship between menu structure and the number of links as well as the number of links and the length of links have significant effects on the efficiency, effectiveness, satisfaction and cognitive load of the users who have visual impairments.
As these factors effect Web navigation and performance of visually impaired users, it is important that Web developers and usability experts are aware of these factors and their relationships. As such they would be guided on what design they could consider to fit the needs of their blind visitors.
Overall, the rising new field of Web usability for the visually impaired is a promising area of research. By not addressing this need immediately, much is being lost in terms of the knowledge and quality of life for the visually impaired hindering them to reach their fullest potential. Much loss is obtained in terms of having a wider range of audience which will in turn translate to potential profits for companies and promotion of quality among human being in ensuring a better future even for the sighted. Measured across, Web usability matters to almost everyone at this point in time, along with the need to appeal of enhanced usability is thereby universal. Making the Web accessible and designing it to be usable for the visually impaired in this broader sense is obviously valuable. A fact of existence, nobody is secured of lifetime visual capabilities.
Adviser:
Ms. Rosemary Seva