Automatic Accessibility Evaluations


This ADE will provide you with a quick introduction to evaluating computer accessibility. As with the Before and After Considering Accessibility ADE, this ADE continues using the Web for practical examples of technology access.

In this ADE your goal will be to determine to what level a specific website adheres to the recommendations of the Web Content Accessibility Guidelines (WCAG) developed by the World Wide Web Consortium (W3C) as part of their Web Accessibility Initiative (WAI).  Most of the work will be done by an online accessibility evaluation tool.

At the end of this ADE, you will have gained familiarity with an automated accessibility validation tool and how to apply generic recommendations to evaluating an interface.

Note: Several abbreviations and acronyms are used on this page. To help you, they have been marked with  <abbr> or <acronym> tags as needed.   Theoretically, two groups of users can benefit from these HTML elements:


WCAG is part of a series of accessibility guidelines, including the Authoring Tool Accessibility Guidelines (ATAG) and the User Agent Accessibility Guidelines (UAAG). WCAG is primarily intended for:

WCAG 2.0 is the current version of WCAG. It is organized around four design principles each having several guidelines which then have success criteria at level 1, 2, or 3. Success criteria are the testable statements that define how Web content conforms to WCAG 2.0 . Each success criteria has a list of sufficient techniques and common failures. If you implement the sufficient techniques, you meet the success criteria for a particular level. If you have one of the common failures, you do not meet the guidelines for a particular level.

WCAG 2.0 also defines three levels of conformance:

More information is available at the Web Accessibility Initiative homepageWCAG will be discussed in more detail later in the course.

To help you to complete this ADE, you may wish to review information from the Before and After Considering Accessibility ADE.

Using AChecker to Evaluate Web site Accessibility:

Wave is a popular and powerful free web accessibility evaluation tool.

The tool is very simple to use: copy a web address into the text box and click the button marked "Check It". After a short wait, a resulting report is provided.

The report has five (5) tabs: Summary, Detals, Reference, Structure, and Contrast. When you first entre a web address, the Summary page comes up once the evaluation is complete. While this gives a quick indication of the  quantity and range of errors an alerts, the Details page is most important for actually seeing what types of accessibility probems a site contains. If you click on the (i)  in the error or alert message in the Details tab it will provide a description of the problem and a link to the WCAG guideline success criteria that is being violated. We will not be concerned about the last two tabs in this ADE.

You will likely find more alerts than errors. This is because some of the WCAG guidelines cannot be evaluated in a fully automated manner. They will require further (manual) investigation to determine whether their related issues applies to the website as well as whether the website complies with the guideline.

We will focus on the Errors, Contrast Errors and Alerts on the Summary and Details tab. 

You will also find information on the sturctue of the website an on ARIA issues that have been identified. ARIA stands for Accessible Rich Internet Applications, which "defines a way to make Web content and Web applications more accessible to people with disabilities. It especially helps with dynamic content and advanced user interface controls developed with HTML, JavaScript, and related technologies." We will not be dealing with ARIA or ARIA issues in this ADE.

What to Do:

  1. To begin, please listen to the short podcast "Is your Document Accessible?" (local copy used with permission).  Then watch the Introduction to Wave.

  2. You will use the website accessibility validation tool Wave to determine to what extent the following websites adhere to the W3C's WCAG 2.0 Web Content Accessibility Guidelines:

  3. The World Wide Web consortium has a page of Web Accessibility Evaluation Tools listing many different automatic accessibility checkers.
    1. Use the Free Web Accessibility Check by AlumniOnline Web Services on the above sites and compare your results
    2. Choose one other web accessibility evaluation tool to explore. Pick one that sounds like it works differently than the two tool that you have already used. Briefly explore how it is different from the other two tools.
    3. Follow the link to Selecting Web Accessibility Evaluation Tools and read the information that it presents. 

What to Hand-in:

Note:  You are not expected to be experienced web programmers.  If you feel something is too difficult based on your current understanding, you may say it is difficult (where appropriate in your answers to questions 2) because the underlying HTML needs to be first researched/learned.
  1. What error(s) and alerts were identified by the Wave tool for each of the Web sites you evaluated and how easy/hard would it be to correct them?
  2. Compare your results from the Wave tool against the results of the AlumniOnline Web Services tool. How do the results differ?
  3. Briefly discuss what you found out about the other tool that you investigated.
  4. Why do you think that the W3C only provides a list of tools and not a tool to help you select a Web Accessibility Evaluation tool?
  5. Feedback
    1. What were your expectations of this ADE?
    2. Did this ADE meet your expectations? Provide a rating between 1 and 7, where 1 means not at all, 4 means somewhat, and 7 means absolutely. Please explain your choice.
    3. Did you feel that the video(s) for this ADE was appropriate? Why or why not? Provide a rating between 1 and 7, where 1 means not at all, 4 means somewhat, and 7 means absolutely. Please explain your choice.
    4. Do you have any suggestions for other possible videos?
    5. Did you feel that the questions above got you to think about the real and serious issues regarding this ADE? Provide a rating between 1 and 7, where 1 means not at all, 4 means somewhat, and 7 means absolutely. Please explain your choice.
    6. If you have any suggestions on how to improve this ADE, please include it here.