100 points to know about...
Digital accessibility

Despite of the increasing awareness of the importance of web accessibility, the majority of websites remain inaccessible or semi accessible.
In this section, we will have a look at the main challenges that might occur while applying the accessibility guidelines for building websites and apps.

These challenges can be split into 4 main groups:

• Challenge 1: Checking Conformance

Often an automatic testing is unable to fully validate conformance with the accessibility success criteria . It is especially challenging to check conformance of large (websites with thousands of pages such as Wikipedia) and dynamic (that are constantly being updated with new content, possibly hundreds of times an hour) websites like Facebook. As consequence an effective validation requires additional time, cost and expertise.
This can be easily seen with the example of an alternative text to image. The automated test checks the existance of the alternative text but not wether its meaning corresponds to the specific image use. It needs human envolvement.

Transcription:
Text Alternatives for Non-Text Content

icon of a paper clip:

• "paper clip": Alternative text that describes the image and passes the automated test.
• "attachment": The correct alternative text if the image appears in content.

---NEW SLIDE---
icon of a globe:

• "globe" or "Planet Earth": Alternative text is a simple descriptive word.
• "preferred language": Alternative text that indicates a specific reason of the image use.

• Challenge 2: Constantly changing sites.

Large websites often have complex content publishing pipelines, which may render content dynamically depending upon a large number of variables (such as what is known about the logged-in user and their content preferences, the geographical location of the user etc.). It is difficult, and may not be feasible, to validate every possible publishing change with a page-level test, which of each can have an impact on whether that particular rendering of the content at that particular moment conforms. Although there are some effective tools used for quality assurance of complex software systems, there is no guarantee of finding all potential bugs, or assuring a software system is bug-free.

• Challenge 3 - Third party content.

Very large, highly dynamic web sites generally aggregate content provided by multiple entities. Many of these are third parties with the ability to add content directly to the website — including potentially every website visitor. The relationship to the 3rd party can be that of a user, a customer, or a professional provider of content such as an advertiser. While the website can provide guidance on how to post content so that it meets accessibility guidance, it is ultimately up to those third parties to understand and correctly implement that guidance. Constraints on page templates and editing facilities can greatly help minimize accessibility issues but, even with automated checks prior to accepting the post, some Success Criteria require human assessment.

• Challenge 4 - Non-Web ICT

The crore principles and many of the accessibility guidelines are broadly applicable outside of the web context. For example, regardless of the technology, information should be perceivable. At the same time, some of the specific guidelines may be difficult to apply to non-web information and communication technologies. Therefore the existing evaluation tools cannot be applicable to these ICT and need human expertise and judgment.