The 5 accessibility tests to run first | Section 508 Trusted Tester: Non-Interference
(almost) everything we learned in the last 5 months
A special instalment from the last study group! The Trusted Tester course provided by the U.S. Department of Homeland Security covers a total of 20 topics of accessibility issues, all based on WCAG and Section 508. Ironically, topic 1 is the last one addressed in the course. This is because you need the knowledge from the other topics to test for this one.
Topic 1: Conforming Alternate Version and Non-Interference
Conforming Alternate Version and Non-Interference is, as the name suggests, divided into requirements for the conforming (meaning: accessible according to all the other tests in the Trusted tester) alternate version and non-interference on the non-conforming content side.
Conforming Alternate Version
To be considered a conforming alternate version, the following must be determined:
Is it fully accessible?
Does it have equivalent information and functionality?
Is the mechanism to reach it accessible?
For most websites, this does not apply as there is usually only one version of the website. In my opinion, this should also be the goal. Except for the examples provided in the course (a data table as the conforming version and a line graph data visualization as the non-conforming one), I cannot think of a scenario in which maintaining two seperate versions instead of a singular accessible one would make sense.
If a conforming alternate version is identified in test ID 1.A, the following 2 IDs check if it is equivalent in information and function (1.B Equivalent Alternative) and if it can be reached in an accessible manner from the non-confirming version (1.C Conformant Mechanism).
Non-Interference (WCAG 5.2.5 Non-Interference)
After checking the conforming version, we turn out attention back to the inaccessible version: Test ID 1.D. Non-Interference covers the most critical accessibility issues that impact users. The purpose of this test is to verify that non-conforming content does not interfere or block the user’s ability to interact with the conforming content. In other words:
Allows users to pause, stop, or control the volume of audio content that is played automatically
Allows users to pause, stop, or hide moving, blinking, or scrolling content
Allows users to stop, pause, hide, or control the frequency of any automatically updating content
Has no flashing content present
Has no keyboard trap.
These requirements are addressed through these test IDs:
Test ID 2.A. Audio Control
Test ID 2.B. Blinking, Moving, and Scrolling
Test ID 2.C. Auto-Updating
Test ID 3.A. Flashing
Test ID 4.C. Keyboard Trap.
2.A. Audio Control (WCAG 1.4.2. Audio Control)
If audio plays automatically for more than 3 seconds, a mechanism must exist to pause, stop, or control the volume independently of the system volume.
The browser’s own option to mute the tab does not count here! Which is why, for example, the existence of a “stop ad” or “mute” button at the top of the page would get a passing grade. But existing alone is not enough, no! You also have to be able find the bright, little button.
If the mechanism exists, but it’s hard to find, it still fails.
2.B. Blinking, Moving, and Scrolling (WCAG 2.2.2. Pause Stop Hide)
Any content that moves, blinks, or scrolls for more than five seconds in parallel with other content requires a pause, stop, or hide mechanism.
Again, an example of good practice would be placing a “stop scrolling” or “pause all moving content” button at the top of the main content, or as a visible button at the top of the page, close to the skip links for keyboard users.
2.C. Auto-Updating (also WCAG 2.2.2.)
Users need a way to pause or hide automatic updates or automatically changing content. Likewise, we cannot have a loss in information when the auto changes are paused.
3.A. Flashing (WCAG 2.3.1 Three Flashes or Below Threshold & 2.3.2. Three Flashes)
The Trusted Tester process has no way to test for the 3 flashes or below the threshold. Non-Interference only says that Flashing must be marked as “does not apply” and if flashing content is present, it is marked “not tested”. But after 5 months of study group, we are better than that! We know that we can run animations and videos through the Photosensitive Epilepsy Analysis Tool by the University of Maryland.
4.C. Keyboard Trap (WCAG 2.1.2. No keyboard trap)
We meet again, old foe. Seriously, keyboard traps keep haunting digital spaces. They are so annoying because one keyboard trap alone can stop you from using a whole website.
Rule of Thumb (or Tab): If you can’t get out of a component with Tab or Escape, and the website doesn’t tell you either, you likely have a trap on your fingers.
The Non-Interference requirements are so important because just one of them alone can sabotage access to the rest of the content.
Once we have a solid foundation, with basic accessibility measures in place, then we can pursue truly inclusive design that minimizes harmful stereotypes and reflects dignity.