Adobe Acrobat Pro Accessibility, Preflight, and PDF/UA

In my classes, I teach that no software checker can fully test that a PDF is compliant with accessibility standards. Here's why:

Software checkers are program/algorithms that can search and evaluate only for pass/fail or yes/no situations. Example: Yes, a PDF is tagged, but are all the essential elements tagged or were some missed or artifacted?  And are the right tags on the elements?

Checkers by Adobe and others have a difficult time determining whether a heading should be <H2> or <H3>, for example. Or if the text is a heading at all.

So we always need a human being with training in accessibile PDF to check the PDF. And it's very helpful to have testers with disabilities test the PDF as well, with not just screen readers but other assistive technologies as well.

Acrobat's Preflight tools can check for technical problems, such as when borders around table cells aren't artifacted correctly by PDF export utilities.

Action Wizard > Make Accessible isn't a great tool to begin with, it's just a list of actions and tools a human accessibility specialist should use. Autotag really doesn't make a viable PDF yet, maybe down the road it will. Those tools have been in Acrobat Pro for a few versions before being gathered under a new name, "Make Accessible."

Hope this helps.