Description

WCAG 2.0

Accessibility audits involve evaluating the webpages in a website against the Web Content Accessibility Guidelines 2.0. These guidelines were created by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C) and are internationally considered the standard in web accessibility. The WCAG is organized in four principles, each of which is further divided into guidelines, with specific success criteria for meeting each guideline. Only the success criteria are normative, which means that web developers must meet them. The principle and guideline text is only informative, meaning that this text is just to help organize the success criteria.

WCAG’s requirements promote accessibility in two ways:

• Some success criteria make content more accessible in a direct way, such as by ensuring that text meets minimum contrast requirements or reading level.
• Other success criteria are more indirect, requiring the website to structure its information so that the accessibility features present in the web browser or screen reader will work properly. For example coding hyperlinks in standard ways (as opposed to mouse-specific ways) enables the keyboard navigation functions provided by most web browsers and by adding programmatic labels to form fields allows that label name to be read by screen readers when the user focuses the form field.

Four principles of accessibility

Guidelines are organized under WCAG’s four leading principles of accessibility regarding web content. These principles can be described as:

1. Perceivable - A site must provide text alternatives for non-text content, alternatives for time-based media, layout alternatives for related or sequential content, and generally make sure all content is easy to see and hear.

2. Operable - A site must provide keyboard access, enough time to read and use content, orientation, clear navigation, and organized content. A site must also operate safely without flashing.

3. Understandable - Content must be readable, consistent, and predictable. Instructions must be clear and helpful.

4. Robust - Content must be compatible with a variety of user agents and assistive technologies. In other words, content shouldn’t focus on the idiosyncrasies of one browser or screen reader at the expense of all the others.

Conforming to WCAG 2.0

Levels of Accessibility

A website’s level of accessibility is based on which of the guidelines listed in the Web Content Accessibility Guidelines (WCAG) 2.0 have been successfully met.

The criteria for meeting WCAG guidelines are organized into three levels:

• Level A - basic accessibility
• Level AA - good accessibility
• Level AAA - advanced accessibility

Most digital accessibility legislation around the world (including in the U.S.) targets Level AA compliance, so this is often the level of accessibility an audit will seek to report on and what we’ll be covering in this course.

The AODA takes a more step-by-step approach, requiring first Level A and then Level AA on a timeline that depends on the type and size of the organization. However, in practice Level A is the actually the “lion’s share” of the work required to get Level AA so in most cases it makes sense to target Level AA from the outset.

Other Conformance Requirements:

WCAG 2.0 includes several other limits on how a site can conform:

• WCAG conformance refers to full pages, not parts of pages.
• If a web page is part of a series of pages (i.e. a process), all pages in the process must conform.
• Web formats beyond HTML* (e.g. SVG) should only be used if there is a reasonable possibility that users will have access to web browsers and assistive technologies that support the accessibility features of that format. *As the default web format, accessibility support for HTML is quite robust.

WCAG Techniques and Known Failures

Each WCAG requirement (success criterion) has a list of techniques for how to successfully meet it, as well as a list of common failures. You can find these lists by following the “How to Meet” and “Understanding” links from each of the WCAG success criteria.

These lists of techniques and failures are very helpful for knowing what to look for when deciding to pass or fail a page on a particular criterion.

Techniques show you examples of how issues can be properly addressed. You can use these to give practical suggestions in your reviews.

It is important to note that, unlike the normative success criteria, the WCAG 2.0 Techniques are informative. In other words, they do not have to be followed, and there may be other ways to meet the success criteria.

Some techniques are labelled sufficient and others are labelled advisory.

• Sufficient techniques are typically sufficient to meet a success criterion. They doesn’t mean they are required, just that if used, they are sufficient.
• Advisory techniques are suggested ways to improve accessibility. They are often very helpful to some users, and may be the only way that some users can access some types of content. Nevertheless, on their own they are not sufficient.

Known failures show examples of things to avoid, which you will come across in your evaluations. Especially when you first start doing reviews, it’s good practice to skim over the lists and look into the specific techniques that apply.

For example, Criteria 2.4.2 requires that “web pages have titles that describe topic or purpose.” If you review techniques and failures for this criterion you will find out:

1. Where to look for the page title element (

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Task

1. Read through the “Understanding Web Accessibility” IDRC Course.
2. Review the following page: http://www.w3.org/WAI/AU/CR20/WCAG2_HTML_Problem_File.html
3. For each example of an unmet success criteria, go through the techniques and failures section and write down (a) how you would check whether each criterion has been met (e.g. for the first image on the page, check for an alt text attribute inside the image element), and (b) what technique you would recommend for solving the issue.
4. Post your completed task here, ensuring that the "Is this for an assignment?" dropdown is set to the name of this lesson.
5. Compare your suggestions to the way they were addressed on the fixed version of the page: http://www.w3.org/WAI/AU/CR20/WCAG2_HTML_Problem_File_Fixed.html

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