W4a09

Transition of Accessibility Evaluation Tools to New Standards

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

Laboratory of HCI for Special Needs

International Cross-Disciplinary Conference on Web Accessibility, W4A 2009

University of the Basque Country

Introduction

Management FrameworkIntroduction

• 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

Updating to WCAG 2.0


Conclusions

Introduction

Management FrameworkIntroduction

• 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



Conclusions

Guidelines Management FrameworkThe 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 FrameworkIntroduction Updating to WCAG 2.0 Conclusions

Guidelines Management FrameworkThe foundations: Unified Guidelines Language (UGL)

• We cannot force users to learn UGL


<checkpoints id="2" title="HTML elements and their attributes"><priority>1</priority><description/><evaluation_type>auto-semi</evaluation_type><techniques id="1"><type>HTML</type><description>Compulsory</description><test_case id="7">

<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="2”><test_case id="8">

<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="not empty"/>


Guidelines Management FrameworkGuidelines Definition Manager

• Technique edition: “for each id attribute in textarea check there is a label where for=id”


1. select textarea tag





1. select textarea tag2. select id attribute





1. select textarea tag2. select id attribute3. select label tag





1. select textarea tag2. select id attribute3. select label tag4. select for attribute





1. select textarea tag2. select id attribute3. select label tag4. 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 Management FrameworkGuidelines 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 URL2. website3. source code


Guidelines Management FrameworkGuidelines 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 URL2. website3. source code


user B

user A

Guidelines Management FrameworkSummary

1: user A creates, searches, shares guidelines


Definition manager

· create· search· share· update

· select guidelines· evaluate

Evaluation component

Guidelinespre-processor

browser server

XQuery1

XQuery2

XQueryn

XQueryi

......

get XQuery2

get XQueryn

Guidelines

repository

1 2

3

5

2: guidelines are stored in a remote repository3: guidelines are transformed into UGL4: UGL are decomposed into XQuery

4

5: user B selects guidelines and evaluates web page


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”

1. guidelines evaluation techniques test cases2. XHTML tag or attribute dependent3. 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



Updating to WCAG 2.0• Decomposing success criteria into test-cases


PrincipleSuccess criteria

automatictest-cases

semi-automatic 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



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

Laboratory of HCI for Special Needs


University of the Basque Country

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Transition of Accessibility Evaluation Tools to New Standards

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W4a09