SELECTING AND USING WEB ACCESSIBILITY EVALUATION TOOLS
Presenter(s)
Shadi Abou-Zahra
World Wide Web Consortium (W3C)
Web Accessibility Initiative (WAI)
2004, Route des Lucioles
Sophia-Antipolis, France
Email: shadi@w3.org
This presentation highlights some of the key
features of Web accessibility evaluation tools and how they can help accomplish
different tasks.
Web accessibility evaluation reviews include a
variety of checks that are often only partially automatable. Moreover, there is
a wide range of Web developers including content authors, graphics designer,
programmers, and others. This broad spectrum of developers who want to fulfill
different evaluation tasks has lead to the production of many types of tools
and tool features. Depending on how rigorous the evaluation review is intended
to be, the complexity of the Web site, the experience and knowledge skills of
the developers, as well as other considerations, some of these tool features
may be more or less relevant in the specific context of the evaluation. This
paper highlights some of the overall considerations and some of the evaluation
tool features to help developers and procurers decide which tools may best
support their needs.
Web accessibility evaluation tools are software
programs that help evaluate Web sites for accessibility. These tools are
sometimes desktop applications that are installed locally on a computer or
online services on remote servers. Furthermore, some of these tools are so
called "plug-ins" that integrate with authoring tools (such as
editors, content management systems, or word processors) or integrate with
browsers. Also assistive technologies such as screen readers or alternative
browsers such as text and voice browsers can be used to evaluate accessibility
even though they are primarily developed for other purposes.
It is important to note that at this point in time,
there is no single Web accessibility evaluation tool that is capable of
automatically assessing all accessibility aspects of Web sites without
interventions from a human. The reason for this is that accessibility
requirements can not always be expressed in formal rules but require human judgement
to determine according to a specific context. For example, it is quite simple
to automatically check if images are associated with alternate descriptions in
HTML but only a human can determine if the description actually makes sense for
that image in that specific Web page. However, tools can significantly improve
the efficiency of evaluation processes by assisting reviewers carry out checks
that can be automated and checks that need to be conducted manually.
CONSIDERATIONS FOR SELECTING TOOLS
There are many different motivations for carrying
out Web accessibility evaluation reviews. Ideally, accessibility evaluations
are carried out throughout the design, development, and maintenance phases of
Web sites. Additionally, more rigorous evaluations are often carried out after
a Web site is launched, possibly through a separate quality assurance team or
external third-parties. There are also different kinds of roles responsible in
the development of accessible Web sites. These roles include Web content authors,
graphics designers, programmers, and project managers (depending on the
organizational structure and development process, developers may have several
responsibilities at once). The following are some consideration to help
identify the context in which the evaluation tools will be used in:
* Who will the evaluation tools be primarily for?
As briefly mentioned, content
authors, graphics designers, programmers, and project managers will be often
looking for different information when evaluating a Web site for accessibility.
* What skills and experience do these users have?
Developers who are new to Web
accessibility may need more feedback about the findings of the tools while this
same information may too verbose for more experienced evaluators.
* How complex is the Web site and how big is it?
Web sites that have a large number
of pages or that make strong use of scripting or advanced Web technologies may
present special challenges that are not addressed by all tools.
* Is there an existing development environment?
Some tools can be integrated into
authoring tools (such as editors, content management systems, or word
processors) or integrate with browsers; or produce EARL or XML reports.
BEHAVIOUR OF EVALUATION TOOLS
Due to the broad diversity in users and user
requirements, evaluation tool developers have implemented different modalities
for interacting with evaluation tools. Some tools provide more than one mode of
operation to help evaluators carry out different tasks (for example automatic
and manual checking). The following are some these modes that are currently
available:
* Generating reports
Summarize the findings in
evaluation reports that are sometimes customizable.
* Step-by-step evaluations
Carry out checks one at a time
either automatically or with the help of a human.
* In-page feedback
Highlight areas or indicate errors
directly on the page to help identify problems.
* Page transformations
Modify the presentation of the
pages such as reading it aloud or enlarging the font.
* Monitoring Services
Run remotely on the Web server and
notify administrators about potential problems.
FEATURES OF EVALUATION TOOLS
There are many features provided by Web
accessibility evaluation tools and it is beyond the scope of this paper to
research each single one. However, the following are broad categories of some
of the types of features:
* Accessibility: How accessible is the evaluation
tool for people with disabilities?
* Checkpoint coverage: Which checkpoints is the
evaluation tool able to adequately address?
* Configuration: How well does the evaluation tool
adapt to the requirements of the users?
* Integration: How well does the evaluation tool
integrate into the Web development environment of the users?
* Policy requirements: Which guidelines and policy
requirements does the evaluation tool support?
* Reliability: How reliable are the results
delivered by the evaluation tool?
* Repair: How well does the evaluation tool assist
developers in repairing inaccessible Web sites?
* Web technology support: How well does the
evaluation tool support the relevant Web technologies?
CONCLUSION
Web accessibility evaluation tools can significantly
improve the efficiency of the evaluation process. However, there are many
different types of developers and motivations for carrying out Web
accessibility evaluations. It is important to analyze and understand the
capabilities of the evaluation tools to get the optimal performance. Also,
tools have limitations because accessibility checks are not always automatable.
It is also important to understand the underlying accessibility requirements in
order to be able to use tools to evaluate them rather than relying on the
output of the tools which may sometimes be imprecise.
REFERENCES
* Selecting Web Accessibility Evaluation Tools
http://www.w3.org/WAI/eval/selectingtools
* Evaluation Tools for Web Content Accessibility
http://www.w3.org/WAI/ER/existingtools
* Web Content Accessibility Guidelines (WCAG)
http://www.w3.org/WAI/intro/wcag
* Evaluation and Report Language (EARL)
http://www.w3.org/WAI/intro/earl
* Web Accessibility Initiative (WAI)
http://www.w3.org/WAI/
* Education and Outreach Working Group (EOWG)
http://www.w3.org/WAI/EO/
* Evaluation and Repair Tools Working Group (ERT WG)
http://www.w3.org/WAI/ER/
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