K. Miesenberger et al. (Eds.): ICCHP 2008, LNCS 5105, pp. 334–337, 2008. © Springer-Verlag Berlin Heidelberg 2008

Web Accessibility - Automatic/Manual Evaluation and Authoring Tools

Introduction to the Special Thematic Session

Helen Petrie1, Christopher Power1, and Gerhard Weber2

1 University of York, Department of Computer Science Heslington, York, YO10 5DD, UK

{Helen.Petrie,CPower}@cs.york.ac.uk 2 Technische Universität Dresden, Fakultät Informatik

Nöthnizer Str. 46, 01602 Dresden, Germany Gerhard.Weber@inf.tu-dresden.de

Abstract. This paper provides an introduction to automatic and manual evalua-tion methods for analysis of web accessibility. The first topic examines the re-cent results in advances in authoring, including modifications to existing CMS systems and new development toolkits. Next, the session explores the accessi-bility of specialized content such as graphics and interface components. The last topic in the session covers the results of the Web Accessibility Benchmarking Cluster of European Union supported projects (WAB-Cluster). Authors discuss technologies needed for automatic as well as manual evaluation.

Keywords: web accessibility, automatic and manual evaluation, authoring tools.

1 Introduction

Browsing the web has become a major activity in everyday life and is being under-taken by more and more people. Learning, reading/writing and shopping are all sup-ported through the web. While we can use other options, often web-based services are considered more convenient in that they can be done at any time from any computer.

People with disabilities can gain a great advantage from the convenience offered by web services, but only if the service is accessible and usable to them. While us-ability techniques have largely remained the same in recent years, making the web accessible to all people has turned out to be a constantly evolving process. The more activities the web supports, the more tools and techniques are required to provide access to them for users with disabilities. These include the development of method-ologies for testing web accessibility; the creation of testing protocols for testing these methodologies; standardizing the methodologies for predictable implementation and validation of the methodologies; and the certification of practitioners and websites according to particular standards (see Figure 1).

Web Accessibility - Automatic/Manual Evaluation and Authoring Tools 335

After almost a decade since the inception of the Web Authoring Content Guide-lines 1.01, the process for making a website accessible is now better understood. These guidelines are in the process of being revised to take into account the progress that has been made in assistive technologies, user agents and web technologies. New processes for testing the accessibility of websites are also integrated into their devel-opment, for example the Unified Web Evaluation Methodology2 (UWEM). Processes such as UWEM support both expert evaluation of accessibility, where human experts need to have standardized and clear procedures for applying the guidelines, as well as automatic evaluation of guidelines through the creation of appropriate algorithms.

Fig. 1. Roadmap of Accessibility Research

Accessibility should be part of any iterative web development process and needs to include evaluations with a representative sample of the users at whom a website is targeted. In this process, different types of users from various user groups should undertake key tasks and test all aspects of the website including its content and func-tionality. It is important to involve different user groups, for example people who are blind or have low-vision, people who are deaf or hard-of hearing, people with physi-cal disabilities and people with specific learning difficulties such as dyslexia, who will all experience different accessibility issues with a website.

Validation of accessibility testing procedures is needed in order to build confidence in the tools supporting experts undertaking testing and in order to understand their limitations. For example, it appears, that the algorithms for calculating appropriate colour combinations need further validation to match the requirements of the users with different colour vision deficiencies3. Assistive technologies (ATs) are now being actively integrated into the validation process; however, the more dynamic the content is, the less usability of ATs can be ignored. For example, screen readers contribute a great deal to the accessibility of embedded applications and scripts in websites, such as Flash-based material. These issues further complicate the creation of guidelines and the validation of websites.

1 http://www.w3.org/TR/WCAG10/ 2 http://www.wabcluster.org/uwem1_2/ 3 http://webcc.fit.fraunhofer.de/downloads/projects/bentoweb/deliverables/BenToWeb_D3.5_rev.pdf

336 H. Petrie, C. Power, and G. Weber

Certification of accessibility testing methodologies, practitioners and the web sites they produce, are all active research areas. Certifications should follow an agreed stan-dard, such as CEN Workshop Agreement CWA 15778-20084. However, this is impeded by the fact that workflows for testing accessibility can become very complicated. For example, if sign language videos need to be analysed then the audio description of videos and the consistency of navigation within a page must also be examined. Such workflows often require several experts to collaborate in order to cover all aspects of a website rich with media such as an online shop as seen in Figure 2.

Fig. 2. An online shopping website with videos, images and interactive application components.

2 Recent Changes in Approaches to Accessibility Testing

Several approaches to web accessibility testing have been attempted but not pursued. Addressing the accessibility issues on a website has been attempted by inserting a proxy server which recognizes accessibility issues and tries to repair them For example, im-proving colour contrast when delivering an adapted website to someone with certain types of visual disabilities or dyslexia via a server can improve accessibility. The repair server can change CSS files or even colour attributes used within the markup language. In place of such a server, some recent research approaches are focusing on client side applications that provide personalized views of web content.

Dynamic sites change their content often. A page may never be delivered in an identi-cal form twice to a user agent and hence its accessibility testing cannot be repeated. An approach to address this situation is to evaluate a representative sample of pages based on the types available; for example, the templates in a content management system.

3 Topics of the Special Thematic Session

The first topic of this Special Thematic Session is the authoring of accessible web-sites. The process of developing an accessible website is discussed by Nedbal and

4 ftp://ftp.cenorm.be/PUBLIC/CWAs/DPA/CWA15778-2008-Feb.pdf

Web Accessibility - Automatic/Manual Evaluation and Authoring Tools 337

Pretz in their contribution on “A Software Solution for Accessible E-Government Portals”. They describe the re-design of a Content Management System for municipal websites and give helpful hints about the necessary layout considerations.

Another example of a system for authoring content is discussed by Doulgeraki et al. in “A novel development toolkit for Unified Web-based User Interfaces”. In this work the authors apply a top-down approach and generate the final personalized user interface from an abstract description language. The EAGER toolkit is also discussed, which is extensible for all kinds of user interfaces including spreadsheet and WYSIWYG editors such as those discussed above.

All types of personalization require a user profiling approach, in particular, infor-mation about the kind of special user needs can be helpful during run-time in an adap-tive system, or when detecting representative user groups for evaluation purposes. Vigoe proposes a novel approach to the “Automatic Detection of User Profiles for Ensuring Personal Web Accessibility”.

The second topic for the Special Thematic Session includes contributions that solve technical challenges in making accessible content on websites. Krüger intro-duces an approach to make Flash applications more accessible while Cantón et al. describe an XML based toolkit to generate accessible interactive multimedia contents. Altmanninger and Wöß report progress towards accessible Scalable Vector Graphics (SVG), where they propose a system for generating accessible graphics. The problem of navigation of 2D/3D structures in web interfaces has been considered by Mátrai et al. in their contribution “Analysis of navigation structures on 2D, 3D and web user interfaces in case of able-bodied users and users with mild intellectual disabilities”.

The final session will address standardization, validation and certification in web-site accessibility, where the Unified Web Evaluation Methodology (UWEM) a result of the WAB-cluster5 supported by the European Union, is presented by Nietzko. Strobbe links the WAB-Cluster with the BenToWeb Project6 and gives an overview on the development of test suites for WCAG 2.0 for better validation of accessibility testing tools. Nietzko presents the findings of another project within the WAB-cluster, the EAIO Project7, regarding the validation of large scale accessibility testing.

5 http://www.wabcluster.org/ 6 http://www.bentoweb.org 7 http://www.eiao.net