WAPM：基于改进层次分析法的网站无障碍评估指标

在网站无障碍评估中,无障碍度量量化综合值反映了网站的无障碍水平。现有研究表明,为不同检测点找到适当的权重存在严重的挑战。目前,一些指标根据WCAG2.0的优先级设置检测点权重,但调查显示,WCAG2.0优先级与关于网站无障碍的可感知性、可操作性、理解性、鲁棒性4项原则相关程度并不显著。此外,网站无障碍评估结果还确认了使用现有指标的网站与4项原则不匹配。为了克服这个限制,本文提出一种称为网站无障碍原则的权重（Web Accessibility Principle Metric,WAPM）,从而更好地将辅助功能评估结果与4项原则的相关程度相匹配,即使用层次分析法对4项原则进行分析,由于检测点与4项原则之间的关联映射存在不完全对应的情况,本文改进层次分析法从而从4项原则中导出最优的检测点权重。实际的网站无障碍评估数据实验验证了WAPM的有效性。     

Exploring perceptions of web accessibility: a survey approach

The equality of access – accessibility – is difficult to quantify, define, or agree upon. Our previous work analysed the responses of web accessibility specialists in regard to a number of pre-defined definitions of accessibility. While uncovering much, this analysis did not allow us to quantify the communities’ understanding of the relationship accessibility has with other domains and assess how the community scopes accessibility. In this case, we asked over 300 people, with an interest in accessibility, to answer 33 questions surrounding the relationship between accessibility, user experience (UX), and usability; inclusion and exclusion; and evaluation, in an attempt to harmonise our understanding of web accessibility. We found that respondents think that accessibility and usability are highly related and also think that accessibility is applicable to everyone and not just people with disabilities. Respondents strongly agree that accessibility must be grounded on user-centred practices and that accessibility evaluation is more than just inspecting source code; however, they are divided as to whether training in ‘Web Content Accessibility Guidelines’ is necessary or not to assess accessibility. These perceptions are important for usability and UX professionals, developers of automated evaluation tools, and those practitioners running website evaluations.     

Web accessibility in the Mid-Atlantic United States: a study of 50 homepages

This paper reports on a study of 50 homepages in the Mid-Atlantic United States to determine what accessibility problems exist. The 50 homepages were evaluated using both the U.S. governments Section 508 guidelines as well as the Web Accessibility Initiatives (WAI) Priority Level 1 of the Web Content Accessibility Guidelines (WCAG). According to both sets of guidelines, 49 out of 50 sites were found to have accessibility problems, although some of the accessibility problems were minor and easy to fix. There are two troubling findings from this study. The Web sites that had the most accessibility problems were organizations in the Web development and information technology field, which ideally should be the leaders in making the Web more accessible. The Web accessibility software testing tools, which are available to assist people in making their Web sites more accessible, are flawed and inconsistent and require large numbers of manual checks, which many developers may not be able to do. More people need to become aware of the topic of Web accessibility, and the testing tools need to be improved so that once people are aware, it is easier for them to move their sites toward full accessibility.     

Exploring the relationship between web accessibility and user experience

Understanding the interplay between the user experience (UX) and Web accessibility is key to design Web sites that, beyond access, could provide a better UX for people with disabilities. In this paper we examine the relationship between UX attributes and Web accessibility. We measured accessibility in two ways: the perceived accessibility as reported by participants and accessibility in terms of conformance to guidelines. Findings uncover that perceived Web accessibility is significantly correlated with 27 of the 35 UX attributes analysed, suggesting these two qualities are closely related. The relationship between UX and conformance to WCAG 2.0 is more elusive: we only found significant correlations between the hedonic attributes original, innovative and exciting.     

The use of guidelines to automatically verify Web accessibility

Accessibility is one of the key challenges that the Internet must currently face to guarantee universal inclusion. Accessible Web design requires knowledge and experience from the designer, who can be assisted by the use of broadly accepted guidelines. Nevertheless, guideline application may not be obvious, and many designers may lack experience to use them. The difficulty increases because, as the research on accessibility is progressing, existing sets of guidelines are updated and new sets are proposed by diverse institutions. Therefore, the availability of tools to evaluate accessibility, and eventually repair the detected bugs, is crucial. This paper presents a tool, EvalIris, developed to automatically check the accessibility of Websites using sets of guidelines that, by means of a well-defined XML structure, can be easily replaced or updated.

Guidelines for Creating Accessible Library Web Pages

ABSTRACT

Library Web developers can improve their Web pages and work towards accessibility by all user groups. This article describes some general accessibility guidelines to follow when creating Web pages. It discusses the recommendations of the World Wide Web Consortium (W3C), called the Web Accessibility Initiatives (WAI). This article focuses attention on the accessibility of Web pages to users with visual impairments, auditory impairments, and mobility impairments. Accessibility guidelines for these user groups are suggested. Another important aspect of creating accessible Web pages is to test the pages during and after development. Online products that test accessibility are discussed as well as additional test methods, such as user input.     

An overview of web accessibility in Greece: a comparative study 2004–2008

This communication reports on the results of a web accessibility audit of public Web sites in Greece. The audit was conducted in 2008 by the Human Computer Interaction Laboratory of the Institute of Computer Science of FORTH, in its capacity as the Greek National Contact Centre of the European Design for All e-Accessibility Network. In an earlier e-Accessibility study in 2004, that evaluated approximately 250 public and commercial Web sites in Greece, 73% of the sample failed to meet the most basic requirements for web accessibility (). Four years later, in the context of a re-audit, a similar sample was examined for compliance with the same web accessibility standard (WCAG 1.0), as set by the Web Accessibility Initiative of the World Wide Web Consortium. The accessibility checks were conducted during the period from March to September 2008. A comparison of the results indicates that although new web development technologies may have been employed, instead of improving the overall status of e-accessibility, this has resulted in a serious deterioration in overall accessibility levels. Such findings—85% of sites failed to comply with Level A—suggest that Greek Web sites are likely to present even more significant access barriers to people with disability than in the past. As Web Accessibility is poorly understood and, until today, new platforms have failed to deliver products that conform to WCAG, the need emerges for a concrete legislative framework to set accessibility specifications for all public Web sites in Greece.     

Accessibility levels of Portuguese enterprise websites: equal opportunities for all?

Web accessibility is growing in importance. We may also find an increasing need for access to web resources by those with some sort of disability. The Web is very important for spreading information and for promoting interaction between the various elements in society. Given this, it is essential that the Web presents itself as a totally accessible resource, so that it can help citizens with disabilities and their integration in society. This obligation should be even greater for enterprises as primarily the Web is used as a marketing and business platform. With this document, we present indicators regarding the [lack of] accessibility levels of Portuguese enterprise websites. This article contains theoretical and background considerations as well as the results of two different studies that the research team undertook. First of all, the research team made a comparison between the 1000 largest Portuguese enterprises (annual sales volume) and the 1000 best Portuguese small and medium enterprises (sales growth and profit) using a specialised software tool and according to Web Content Accessibility Guidelines (WCAG) 1.0; the research team then also considered WCAG 2.0 and its impact on enterprise Web accessibility. In the second study (qualitative in nature), focus group interactions led to a set of recommendations towards greater accessibility.     

Migrating from WCAG 1.0 to WCAG 2.0 - A comparative study based on Web Content Accessibility Guidelines in Taiwan

The primary purpose of this research was to explore a comparative analysis of the “Web Content Accessibility Guidelines (WCAG)” standard in Taiwan and the international WCAG standards (WCAG 1.0/WCAG 2.0). The WCAG in Taiwan was established by the Research, Development and Evaluation Commission (RDEC), Executive Yuan in 2002. The WCAG 1.0 was established by the Web Accessibility Initiative (WAI, an organization that created the Web Content Accessibility system) of the World Wide Web Consortium (W3C), and became a W3C standard on May 5, 1999. The WCAG 2.0 became a W3C standard on December 11, 2008.The WCAG in Taiwan was established based on the contents of the WCAG 1.0. However, as the WCAG 2.0 was announced in 2008, check standards based on the WCAG 1.0 were facing revision in all aspects. Therefore, this study aimed at analyzing and comparing the differences between the WCAG 2.0 and the WCAG standards in Taiwan. Utilizing “human check” based on the WCAG 2.0 standard, this study assessed disabilities-related websites conforming to the WCAG standard in Taiwan. Results suggested that migrating from WCAG in Taiwan (based on WCAG 1.0) to WCAG 2.0 does not require a full range revision of webpage design. Suggestions given to disabilities-related websites in Taiwan for developing and providing more complete web accessibility included: (1) websites without accessible design should directly follow the WCAG 2.0 standard in developing web accessibility; (2) future promotion of web accessibility should include all educational institutes and related associations/organizations.For future studies, the resource availability for the disabled and the government achievement in web accessibility after WCAG 2.0 is implemented in Taiwan are topics worth of investigation. Expert opinions and user feedbacks should be included to reflect the actual needs of people with disabilities.     

Improving web accessibility: a study of webmaster perceptions

Large percentages of web sites continue to be inaccessible to people with disabilities. Since tools and guidelines are available to help designers and webmasters in making their web sites accessible, it is unclear why so many sites continue to be inaccessible. In this paper, we present the “Web Accessibility Integration Model,” which highlights the multiple points within web development where accessibility can be incorporated or forgotten. It is uncertain why webmasters do not use the various tools and guidelines that currently are available for making web sites accessible. A survey was created, and data was collected from 175 webmasters, indicating their knowledge on the topic of web accessibility and the reasons for their actions related to web accessibility. Findings and future directions for research are discussed.     

Validating WCAG versions 1.0 and 2.0 through usability testing with disabled users

The Web Content Accessibility Guidelines (WCAG) by the Web Accessibility Initiative (WAI) has become the de-facto standard for accessibility on the Web. WCAG version 1.0 has become significant both as a practical tool and as an academic set of principles and is presently the basis of Web accessibility evaluations and guidelines in many countries. WCAG version 2.0 was released in 2008. This paper reports on a study that empirically validated the usefulness of using WCAG as a heuristic for website accessibility. Through controlled usability tests of two websites with disabled users (N?=?7) and a control group (N?=?6), it was found that only 27% of the identified website accessibility problems could have been identified through the use of WCAG 1.0. A similar analysis of conformance to WCAG 2.0 showed a marginal 5% improvement concerning identified website accessibility problems. Compensating for the low number of test subjects with confidence tests gave results that were still low (42% for WCAG 1.0 and 49% for WCAG 2.0, with 95% confidence). It is concluded from this that the application of WAI accessibility guidelines is not sufficient to guarantee website accessibility. It is recommended that future versions of the accessibility guidelines should be based on empirical data and validated empirically and that WAI expand their definition of accessibility to include “usability for all” in accordance with ISO 9241-171:2008.     

One year older, but not necessarily wiser: an evaluation of homepage accessibility problems over time

A large number of users with disabilities use assistive technology devices to browse the web. However, the use of assistive technologies can only be successful when the web sites are developed in such a way that they are compatible with such devices. Guidelines exist for creating accessible web sites. However, they are seldom followed, and current levels of web accessibility are low. Therefore, the question arises as to which is the major cause of inaccessibility, and how accessibility features of web sites evolve over time. A set of 50 web sites has been studied over time to determine if accessibility improves or declines. This research-in-progress paper presents a comparison of the results obtained in 2002 and 2003. Such a comparison leads to the conclusion that, in the time period of 1 year, the 50 web sites have actually become more inaccessible. Implications for developers, webmasters, and educators are also discussed in the paper.

Investigating the problems faced by older adults and people with disabilities in online environments

Irresponsible and inaccessible web design causes unnecessary problems to certain website users. By applying the web content accessibility guidelines to a website the amount of possible users who can successfully view the content of that site will increase especially for those who are in the disabled and older adult categories of online users. We present the results of assessing the compliance of a selection of websites with guidelines set out by the Web Accessibility Initiative (WAI). It was found that most sites evaluated were inaccessible to those with disabilities. Only one of the selected sites passed all three priority levels set out by the WAI. In many cases, minor modifications to sites will make them accessible to people with disabilities. Therefore it can only be speculated that the reasons for lack of conformance may vary from lack of awareness of the issue, time constraints or the general stress of having to keep up with new technologies. Companies who overlook users with disabilities however may be doing so at long-term risk to their legal position, public image and ultimately business success.     

Investigating the problems faced by older adults and people with disabilities in online environments

Irresponsible and inaccessible web design causes unnecessary problems to certain website users. By applying the web content accessibility guidelines to a website the amount of possible users who can successfully view the content of that site will increase especially for those who are in the disabled and older adult categories of online users. We present the results of assessing the compliance of a selection of websites with guidelines set out by the Web Accessibility Initiative (WAI). It was found that most sites evaluated were inaccessible to those with disabilities. Only one of the selected sites passed all three priority levels set out by the WAI. In many cases, minor modifications to sites will make them accessible to people with disabilities. Therefore it can only be speculated that the reasons for lack of conformance may vary from lack of awareness of the issue, time constraints or the general stress of having to keep up with new technologies. Companies who overlook users with disabilities however may be doing so at long-term risk to their legal position, public image and ultimately business success.     

Personalizable edge services for Web accessibility

Web Content Accessibility guidelines by W3C (W3C Recommendation, May 1999. ) provide several suggestions for Web designers regarding how to author Web pages in order to make them accessible to everyone. In this context, this paper proposes the use of edge services as an efficient and general solution to promote accessibility and breaking down the digital barriers that inhibit users with disabilities to actively participate to any aspect of society. The idea behind edge services mainly affect the advantages of a personalized navigation in which contents are tailored according to different issues, such as client’s devices capabilities, communication systems and network conditions and, finally, preferences and/or abilities of the growing number of users that access the Web. To meet these requirements, Web designers have to efficiently provide content adaptation and personalization functionalities mechanisms in order to guarantee universal access to the Internet content. The so far dominant paradigm of communication on the WWW, due to its simple request/response model, cannot efficiently address such requirements. Therefore, it must be augmented with new components that attempt to enhance the scalability, the performances and the ubiquity of the Web. Edge servers, acting on the HTTP data flow exchanged between client and server, allow on-the-fly content adaptation as well as other complex functionalities beyond the traditional caching and content replication services. These value-added services are called edge services and include personalization and customization, aggregation from multiple sources, geographical personalization of the navigation of pages (with insertion/emphasis of content that can be related to the user’s geographical location), translation services, group navigation and awareness for social navigation, advanced services for bandwidth optimization such as adaptive compression and format transcoding, mobility, and ubiquitous access to Internet content. This paper presents Personalizable Accessible Navigation (Pan) that is a set of edge services designed to improve Web pages accessibility, developed and deployed on top of a programmable intermediary framework. The characteristics and the location of the services, i.e., provided by intermediaries, as well as the personalization and the opportunities to select multiple profiles make Pan a platform that is especially suitable for accessing the Web seamlessly also from mobile terminals.

Determinants of employees’ intention to exert pressure on firms to engage in web accessibility

Web accessibility can help reduce the digital divide between persons with disabilities and the web by providing easy access to information on the Internet. Providing web accessibility can be an important element that manifests a firm's corporate social responsibility (CSR) and employees can play a vital role in this process. This paper examines how employees can impact a firm's decision to fulfil their CSR regarding web accessibility. We propose that employees’ intention to exert pressure on a firm is primarily influenced by three psychological needs, namely need for control, need for belonging, and need for meaningful existence. Additionally, perceived importance of CSR moderates the relationship between need for meaningful existence and intention. We empirically test the research model using data collected from 106 Chinese employees. The results suggest that for employees to pressure their firms to improve the accessibility of their websites, it is imperative to enhance their perceived importance of web accessibility, and their need for belonging and for a meaningful existence. We present the theoretical and managerial implications arising from our findings.     

An exploratory study of the accessibility of state government Web sites

This paper focuses on Web accessibility. Relevant legislation and judicial decisions are reviewed, and prior empirical research is presented. This study presents the results from the Web accessibility analysis of the home pages of the 50 states and the District of Columbia. It found that twenty-nine percent of the home pages do not meet the requirements for Conformance Level A Web accessibility. Only one state meets Conformance Level AA standards, which are the minimum standards recommended for Web accessibility, and no state meets Conformance Level AAA standards. This paper also discusses how to address common accessibility problems.

The Expertise Effect on Web Accessibility Evaluation Methods

Web accessibility means that disabled people can effectively perceive, understand, navigate, and interact with the web. Web accessibility evaluation methods are needed to validate the accessibility of web pages. However, the role of subjectivity and of expertise in such methods is unknown and has not previously been studied. This article investigates the effect of expertise in web accessibility evaluation methods by conducting a Barrier Walkthrough (BW) study with 19 expert and 57 nonexpert judges. The BW method is an evaluation method that can be used to manually assess the accessibility of web pages for different user groups such as motor impaired, low vision, blind, and mobile users.

Our results show that expertise matters, and even though the effect of expertise varies depending on the metric used to measure quality, the level of expertise is an important factor in the quality of accessibility evaluation of web pages. In brief, when pages are evaluated with nonexperts, we observe a drop in validity and reliability. We also observe a negative monotonic relationship between number of judges and reproducibility: more evaluators mean more diverse outputs. After five experts, reproducibility stabilizes, but this is not the case with nonexperts. The ability to detect all the problems increases with the number of judges: With 3 experts all problems can be found, but for such a level 14 nonexperts are needed. Even though our data show that experts rated pages differently, the difference is quite small. Finally, compared to nonexperts, experts spent much less time and the variability among them is smaller, they were significantly more confident, and they rated themselves as being more productive. The article discusses practical implications regarding how BW results should be interpreted, how to recruit evaluators, and what happens when more than one evaluator is hired.

Supplemental materials are available for this article. Go to the publisher's online edition of Human–Computer Interaction for statistical details and additional measures for this article.     

Browsing shortcuts as a means to improve information seeking of blind people in the WWW

This paper presents a “Semantic Web application framework” which allows different applications to be designed and developed for improving the accessibility of the World Wide Web (WWW). The framework promotes the idea of creating a community of people federating into groups (ontology creators, annotators, user-agent developers, end-users) each playing a specific role, without the coordination of any central authority. The use of a specialised voice web browser for blind people, called SeEBrowser, is presented and discussed as an example of an accessibility tool developed based on the framework. SeEBrowser utilises annotations of web pages and provides browsing shortcuts. Browsing shortcuts are mechanisms, which facilitate blind people in moving efficiently through various elements of a web page (e.g. functional elements such as forms, navigational aids etc.) during the information-seeking process, hence operating effectively as a vital counterbalance to low accessibility. Finally, an experimental user study is presented and discussed which evaluates SeEBrowser with and without the use of browsing shortcuts.     

A web accessibility assessment on the Texas public school system

As the World Wide Web becomes one of the main communication channels between school districts and their community of stakeholders, the need to provide equal access and equal opportunity to people with disabilities is no longer just an ethical issue, but also a legal obligation. This communication reports on testing the 1,117 entities within the Texas public school system using the Bobby Software. The results show that most of the web sites fail to meet the minimum required standards: Section 508 guidelines and Web Content Accessibility Guidelines priorities. Each violation is counted, a breakdown of the data is given, and finally a global approach for designing the web sites is proposed for the Texas public school system to enhance its web accessibility.