Motivation
- Managing accessibility becomes increasingly difficult as the Web site size and complexity grows
- Evaluation processes are often separated from the development processes thus increasing overhead
- There is a strong need to combine expertise of human and tools to optimize evaluation processes
Evaluation Methods
Different methods for evaluating Web accessibility have pros and cons, best is to use a combined approach:
- Automatic Testing
- Efficient but has serious limitations
- Expert Testing
- Overcomes limitations but less efficient
- User Testing
- Very effective but requires high expertise
- Comprehensive Testing
- Optimizes effectiveness and efficiency
Webmaster Bottleneck
The responsibility of evaluating Web site accessibility is ideally distributed across the development:
- Layout Designer
- Visual and structural aspects
- Backend Programmer
- Interaction and functionality aspects
- Content Author
- Content and informational aspects
- Quality Assurance
- Overall accessibility monitoring
Evaluation Reports
Different methods for evaluating Web accessibility have pros and cons, best is to use a combined approach:
- Developers
- To identify and repair barriers
- Managers
- To track and monitor progress
- Public
- To support conformance claims
EARL Model
EARL Objectives
- Build on Semantic Web technologies
- Provide a royalty-free Web standard
- Ensure platform and vendor neutrality
- Purpose is generic quality assurance
- Should be extensible for any domain
...especially for Web accessibility
EARL Structure
EARL is an RDF Schema with these classes:
- Assertor
- Person, tool, organization, or other entity making claims
- Subject
- Web site, page, Delivery Unit, or resource being tested
- Test
- Testable assertions such as Requirements or Test Cases
- Result
- Outcome of the test on the subject by the assertor
EARL Statement
An example EARL assertion could look like the following:
- Assertor
- HTML Validator version 0.9.3 at http://validator.w3.org
- Subject
- http://www.example.org/page.html with HTTP headers
- Test
- Test Case 7.5.2, check for wellformed XML structure
- Result
- Failed, line 12 col 3, message "tag <em> not closed"
Topology Model
EARL is compatible with any:
- Internal Repository
- Confidential QA test results
- Self-Declarations
- Disclosed conformance claims
- Third-Party Certification
- Trusted sources for claims
- Proxy Services
- Query for features
Additional Benefits
EARL also provides additional benefits besides reporting:
- Integrate evaluation and authoring tools
- Encourage the development of evaluation tools
- Encourage the development of analysis tools
- Provide a method for profiling Web resources
Current Status
- EARL 1.0 Schema
- Next Working Draft may be Last Call
- EARL 1.0 Guide
- Early draft available, no open issues
- Other Resources
- Requirements, HTTP in RDF Note
- Implementations
- Tools support is growing but need more prototypes
