The WCAG-EM Report Tool is an app created for accessibility auditors to guide them in the process of auditing websites for accessibility using the WCAG Evaluation Methodology. As any app should, the data is stored in a common format that can be saved and loaded back into the app.
At it's core, the WCAG-EM Report Tool uses the Evaluation And Report Language (EARL), developed by the W3C. EARL is build on top of the Resource Description Framework (RDF), which means it can be expressed using different formats such as XML, Turtle and JSON-LD. The WCAG-EM Report Tool requires significantly more information than just the results of individual tests. It has data about the evaluation itself, such as the scope, sample, title, summary, etc. The EARL results are part of an evaluation, and are therefore embedded within data like so:
{
"dct:title": 'My Website Audit',
"scope": { /* EvaluationScope */ },
// ...
"auditResults": [ /* earl assertions */ ]
}Though RDF can be expressed in different formats, the WCAG-EM Report Tool can only load evaluation data expressed as JSON-LD.
Concepts of WCAG-EM are mapped to the steps in the WCAG-EM document. For example, the first step of WCAG-EM is to define scope, so 'scope' is mapped to http://www.w3.org/TR/WCAG-EM/#step1.
The WCAG-EM Data format contains several classes. Most of them are new to WCAG-EM, with a few of them are borrowed from other schemas and decorated with different properties. These classes and the properties they are given in the WCAG-EM Report Tool are described in the following sections.
Several namespaces are used in the definition of the classes. The default namespace in a JSON-LD context is described with @vocab. Any names, other than 'text' and 'URL', are part of this namespace. The following namespaces are used:
- @vocab: (the default) http://www.w3.org/TR/WCAG-EM/#
- WCAG2: http://www.w3.org/TR/WCAG20/#
- dct: http://purl.org/dc/terms/
- sch: https://schema.org/
- earl: 'http://www.w3.org/ns/earl#
In addition to these namespaces, there are three possible values for the WCAG 2 conformance target:
- level_a: http://www.w3.org/WAI/WCAG2A-Conformance
- level_aa: http://www.w3.org/WAI/WCAG2AA-Conformance
- level_aaa: http://www.w3.org/WAI/WCAG2AAA-Conformance
An evaluation is the process of testing the accessibility of a website according to WCAG-EM. Objects of type Evaluation contains the data generated as part of the evaluation.
Special: The @language property of JSON-LD will be used by the Report Tool to identify the language used in the evaluation.
| Property | Type | Description |
|---|---|---|
| dct:title | text | Title of the evaluation report |
| dct:summary | text | Executive summary |
| dct:creator | earl:Assertor | Author and creator of the evaluation |
| dct:date | text | Completion date of the evaluation |
| commissioner | text | Person/organization who commissioned the evaluation |
| WCAG2:reliedupondef | WCAG2:technologydef | Web technologies the website relies upon for providing it's content |
| step1 | EvaluationScope | Scope of the evaluation |
| step2a | text | Common pages of the website |
| step2b | text | Essential functionality of the website |
| step2c | text | Variety of page types of the website |
| step2e | text | Other relevant pages of the website |
| step3a | Sample | Structured sample pages |
| step3b | Sample | Random sample pages |
| step4 | earl:Assertion | Audit results of the evaluation |
| step5b | text | Evaluation specifics |
{
"@type": "Evaluation",
"@language": "en",
"dct:title": "Evaluation of example.org",
"dct:summary": "This website is very accessible.",
"dct:creator": "John Doe",
"dct:date": "2008-12-11",
"commissioner": "Example Inc.",
"WCAG2:reliedupondef": [
{ /* WCAG2:technologydef 1 */ },
{ /* WCAG2:technologydef 2 */ }
],
"step1": { /* EvaluationScope */ },
"step2a": "Home, contact",
"step2b": "The web shop",
"step2c": "PDF, tables, video's",
"step2e": "Copyright page, Accessibility statement",
"step3a": { /* Sample (structured) */ },
"step3b": { /* Sample (random) */ },
"step4": [
{ /* earl:Assertion 1 */ },
{ /* earl:Assertion 2 */ }
],
"step5b": "Results of the evaluation can be found at example.org/archive/123"
}Objects of type EvaluationScope described what should and what should not be considered as part of the evaluation. This includes both a definition of the website that is to be tested, as well as the exact requirements against which the website is tested.
| Properties | Type | Description |
|---|---|---|
| WCAG2:set-of-web-pagesdef | sch:WebSite | Website that is to be evaluated |
| step1b | URL (level) | Conformance target |
| step1c | text | Accessibility support baseline |
| step1d | text | Additional evaluation requirement |
{
"@type": "EvaluationScope",
"WCAG2:set-of-web-pagesdef": { /* WebSite */ },
"step1b": "http://www.w3.org/WAI/WCAG2AA-Conformance",
"step1c": "IE + Jaws. Firefox & Chrome + NVDA, Safari + VoiceOver",
"step1d": "Including Level AAA success criteria of principle 1",
}A WebSite is a set of related web pages and other items typically served from a single web domain and accessible via URLs.
| Properties | Type | Description |
|---|---|---|
| step1a | text | Scope of the website |
| sch:name | text | The name of the item |
{
"@type": ['earl:TestSubject', "sch:WebSite"],
"step1a": "All pages located at www.example.com",
"sch:name": "Example.com corporate"
}A subset of web pages within the scope of the website that is to be audited.
| Properties | Type | Description |
|---|---|---|
| WCAG2:webpagedef | sch:WebPage | Resourced to be rendered in a user agent |
{
"@type": "Sample",
"WCAG2:webpagedef": [
{ /* Sample page 1 */ },
{ /* Sample page 2 */ }
]
}A web page is an document or application made available over http or https.
| Properties | Type | Description |
|---|---|---|
| @id | URL | URL or internal ID to be reffered to from assertions |
| dct:title | text | Title for the webpabe |
| dct:description | text | Description of how to show the page |
| dct:source | URL | Source (url) of the web page |
| reporter:tested | boolean | If the page is fully tested yet |
{
"@type": ['earl:TestSubject', "sch:WebPage"],
"dct:title": "Example Home",
"dct:description": "http://example.com/ (mobile version)",
"dct:source": "http://example.com/",
"reporter:tested": false,
}Mechanism for encoding instructions to be rendered, played or executed by user agents.
| Properties | Type | Description |
|---|---|---|
| @id | URL | Referenc to the technology specification |
| dct:title | text | Title by which the technology is known |
{
"@type": "WCAG2:technologydef",
"@id": "http://www.w3.org/TR/html5/",
"dct:title": "HTML 5"
}An assertor is an entity such as a person, a software tool, an organization, or any other grouping that carries out a test collectively. For more details see: http://www.w3.org/TR/EARL10-Schema/#Assertor
The WCAG-EM Report Tool fills in the foaf:name property of whichever
type was used. When creating an evaluation, the 'foaf:Person' class is used.
Assertions are described according to EARL and will also include a TestResult. For more details see: http://www.w3.org/TR/EARL10-Schema/#Assertion
Important note: To refer to WCAG 2 success criteria, the IDs of given to their definition in the official WCAG 2 specification are used. For example, the definition of Success Criterion 1.1.1 is http://www.w3.org/TR/WCAG20/#text-equiv-all
The earl:subject is a reference to the @id of either a WebPage in either of the Sample object, or the WebSite object which is part of the EvaluationScope. If it is neither of these, they will not be included in the WCAG-EM Report Tool.
The use of 'dct:hasPart' to indicate a relationship between the assertions with the website as it's subject, and the assertions with webpages as their subject is not part of the EARL specification. The WCAG-EM Report Tool uses this relationship to determine how to group page assertions. Because all assertions refer to a 'test' this relationship is redundant and will therefore be dropped in a future version of the WCAG-EM Report Tool.
{
"@type": "earl:Assertion",
"earl:test": "WCAG2:text-equiv-all",
"earl:assertedBy": "_:evaluator",
"earl:subject": "_:website",
"earl:result": {
"@type": "earl:TestResult",
"earl:outcome": "earl:failed",
"dct:description": "Images must have a text alternative"
},
"earl:mode": "manual",
"dct:hasPart": [
{ /* earl:Assertion for WebPage 1 */ },
{ /* earl:Assertion for WebPage 2 */ }
]
}This boolean value is used by the Report Tool to track if a WebPage is tested.