Transition of Accessibility Evaluation Tools to New Standards

Transition of Accessibility
Evaluation Tools to New Standards

A. Aizpurua, M. Arrue, Markel Vigo, and J. Abascal

University of the Laboratory of HCI
Basque Country for Special Needs

International Cross-Disciplinary Conference on Web Accessibility, W4A 2009

Introduction
• The advent of WCAG 2.0 calls for accessibility guidelines
review tools adaptation and update
• It is expected that international policies will adopt WCAG 2.0
• How to do this transition in the less painful way
• An interactive framework for guidelines management is
provided
• Help users in the process of guideline creation and edition

Introduction Management Framework Updating to WCAG 2.0 Conclusions


Introduction
• Web application universally accessible from the browser
• WCAG 1.0 compliant and empowers people with disabilities to
contribute
• Centralized system so that users, developers and practitioners
can share information
• It contains an evaluation component
• No need for evaluation engine update

Introduction Management Framework Updating to WCAG 2.0 Conclusions


Guidelines Management Framework
The foundations: Unified Guidelines Language (UGL)
• Unified Guidelines Language (UGL), a XML-based language to
define guidelines.
• Developed by considering diverse guideline sets:
→ General purpose: WCAG 1.0 and IBM Accessibility Guidelines
→ Device: Mobile Web Best Practices 1.0
→ Application: Accessible Educational Sites [Freed et al., 2003]
→ Specific audiences: usability guidelines for the elderly [Kurniawan and
Zaphiris, 2005]

• Flexible enough to handle heterogeneous guidelines
• We cannot force users to learn UGL

Management Framework
Introduction Updating to WCAG 2.0 Conclusions


The foundations: Unified Guidelines Language (UGL)
• We cannot force users to learn UGL
<checkpoints id=quot;2quot; title=quot;HTML elements and their attributesquot;>
<priority>1</priority>
<description/>
<evaluation_type>auto-semi</evaluation_type>
<techniques id=quot;1quot;>
<type>HTML</type><description>Compulsory</description>
<test_case id=quot;7quot;>
<type>7</type>
<evaluation_type>auto</evaluation_type>
<evaluation_result>error</evaluation_result>
<element>
<label>IMG</label>
<test_e>check attribute</test_e>
<related_attribute>
<atb>alt</atb>
<test_a>compulsory</test_a>
</related_attribute>
</element>
</test_case>
</techniques>
<techniques id=quot;2”>
<test_case id=quot;8quot;>
<type>8</type>
<evaluation_type>auto</evaluation_type>
<evaluation_result>error</evaluation_result>
<element>
<label>FRAME</label>
<test_e>check attribute</test_e>
<related_attribute>
<atb>title</atb>
<test_a>compulsory</test_a>
<content analysis=quot;not emptyquot;/>



Guidelines Definition Manager
• Technique edition: “for each id attribute in textarea check there
is a label where for=id”
1. select textarea tag



2. select id attribute



3. select label tag



3. select label tag
4. select for attribute



3. select label tag
4. select for attribute
5. define element order



• Guidelines can be shared: general search, specific search,
mark-up dependent search



• Search results: guidelines can be retrieved, edited and used



Guidelines Pre-processor
• Created guidelines are stored in a centralized database
• Data aretransformed into UGL files
• Decompose resulting UGL file into XQuery queries
• This process does not require human intervention
Guidelines Evaluation Component
• Select the guidelines
• Type URL
• Evaluation type:
1. single URL
2. website
3. source code



Guidelines Pre-processor
• Created guidelines are stored in a centralized database
• Data are transformed into UGL files
• Decompose resulting UGL file into XQuery queries
• This process does not require human intervention
Guidelines Evaluation Component
• Select the guidelines
• Type URL
• Evaluation type:
1. single URL
2. website
3. source code



Summary
2: guidelines are guidelines and evaluates web page
3: user A selects stored intoremote repository
1: UGL are decomposedin a shares UGL
5:
4: B creates,transformedXQuery
searches, into guidelines
browser server
· create
1 2
· search
· share
Definition
user A
· update
manager Guidelines
repository

3
Guidelines
pre-processor

· select
Evaluation XQuery1
guidelines
user B
component
· evaluate 4
XQuery2
get XQuery2

...
5
XQueryi

...
XQueryn



Updating to WCAG 2.0
• Case study with WCAG 2.0
• Taking advantage of the features of the guidelines
management framework
• Test-case definition: ”Test-cases are the minimum pieces of
knowledge required for the evaluation of guidelines”
guidelines  evaluation techniques  test cases
1.
2. XHTML tag or attribute dependent
3. Test-cases can be grouped into test-case types
 IMG [@alt]
 TABLE [@summary]
4. there is a predefined evaluation pattern for each test-case type

• Focusing on automatic and semi-automatic issue

Introduction Management Framework Conclusions


• Decomposing success criteria into test-cases
Success automatic semi-automatic
Principle criteria test-cases test-cases
Perceivable 22 17 38
Operable 20 8 16
Understandable 17 10 9
Robust 2 4 3
Total 61 39 66

• Results obtained with the guidelines management framework:
 Automatic test-cases: 55%
 Semi-automatic: 16%



• Results obtained with the guidelines management framework:
 Automatic test-cases: 55%
 Semi-automatic: 16%

• It is not a limitation of UGL but of the management framework

• They can be manually included
• By adapting the framework almost all automatic test cases can
be defined
• Except those that are not hypertext dependent
 E.g.:”check that the value of longdesc is a valid URI ”

• Strike a balance between guiding the user or letting him free



Conclusions
• The framework for guidelines management is a sound tool to
share and spread knowledge on web accessibility
• Cooperative tool enabling collaboration between researchers,
practitioners and users
• It can be used in the development process for:
 Search for the set of guidelines which is relevant to the current
development
 Remove guideline overlap and verify coherence
 Perform frequent accessibility evaluations
• WCAG 2.0 deployment has been less painful
• Updating the framework in order to express more test-cases



Transition of Accessibility
Evaluation Tools to New Standards

Any question?

A. Aizpurua, M. Arrue, Markel Vigo, and J. Abascal

University of the Laboratory of HCI
Basque Country for Special Needs


Transition of Accessibility Evaluation Tools to New Standards

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