The most common PDF accessibility errors in higher education course readings are mismatched reading order, missing or meaningless alt text, data tables without header markup, and scanned pages with no text layer. A file can contain all four and still pass a basic automated check, which is why these errors often go unnoticed until a screen reader user opens the reading.
None of this is abstract for the student on the other end. A blind student assigned the same reading as everyone else should not have to email a professor and wait three days for an accessible copy that arrives after the class discussion has already moved on.
Most lists of PDF accessibility errors stop at naming which ones a scanner misses. The distinction that actually determines whether your remediation process holds up in an audit is which of these a checker can flag after the fact versus which ones only surface when a real screen reader user opens the file — that gap is exactly where an automated-only workflow fails.
What are the most common PDF accessibility errors, and how do you actually catch them?
The ten failures below account for nearly every complaint we see in higher education course-material audits. Naming them isn’t the hard part — knowing how to verify each one without just re-running the same scanner is.
| Error | Why a checker misses it | How to actually catch it |
| Reading order doesn’t match the visual layout | Confirms tags exist, not their sequence | Read the file start to finish with NVDA or Voiceover, not just the printed page |
| Scanned page with no text layer | Some scanners flag missing tags, not missing text | Try selecting text on the page — if nothing highlights, there’s no OCR layer |
| Alt text blank or copied from the file name | Sees an alt attribute exists, not whether it’s meaningful | Read each alt tag aloud and ask whether it replaces the image’s purpose |
| Data table with no header scope | Passes if any header row exists, scope or not | Tab through the table with a screen reader and listen for column context on each cell |
| Headings styled bold instead of tagged | Looks correct visually; a scanner can’t see intent | Open the tag tree and confirm each heading is a real Hn tag, not styled text |
| Form field with no label | Flags missing labels only for recognized field types | Tab to every field and confirm the announced name matches its purpose |
| No document language set | Rarely checked by a basic scan at all | Check document properties for a language attribute before publishing |
| Color used as the only signal | Scanners check contrast ratio, not meaning | Ask whether the message still makes sense viewed in grayscale |
| “Click here” links | Passes link-text checks that only flag empty links | Read link text out of context and see if the destination is still clear |
| Missing document title | Often skipped because the file still opens fine | Check what the browser tab and screen reader actually announce on open |
Why do these errors slip past automated checkers in the first place?
Because most tools test whether a tag exists, not whether it’s correct. Automated scanning reliably detects roughly a third of WCAG issues; judgment calls like reading order, alt text quality, and table structure still need a person reading the file.
| Symptom | Why it happens | What works |
| Same error reappears every semester | Fix is applied to the exported PDF while the source stays broken | Remediate the Word, InDesign, or PowerPoint source so every future export is born accessible |
| Backlog looks too large to size | No inventory of what’s actually in current use | Apply the preexisting-document and archived-content tests before remediating anything |
Does fixing these errors satisfy ADA Title II compliance for course material?
Not by itself, but it’s the foundation of it. Public colleges and universities generally must meet WCAG 2.1 Level AA for content delivered through a learning management system (LMS) by April 26, 2027, and course readings have no exception under the rule. See our full breakdown of the deadline and its five exceptions in ADA Title II compliance for higher education. Fixing the ten errors above resolves the technical failures an audit will flag; the deadline is the reason to prioritize the fix now rather than next semester.
What should administrators check first in a PDF backlog?
- Pull a sample of your most-assigned readings and run them through PAC or Acrobat’s accessibility checker, then verify by ear with NVDA or Voiceover.
- Flag every file where the automated result says “pass” but no one has done a manual reading-order or table check.
- Fix the source file — the original Word, InDesign, or PowerPoint document — wherever it still exists, rather than patching the exported PDF.
- Add WCAG 2.1 AA and PDF/UA conformance language to your next course-material procurement cycle.
If your team doesn’t have time to manually screen-reader test every file in a course-reading backlog, ContentA11Y provides accessible PDF services that remediate PDFs, slide decks, and Word source files to WCAG 2.1 AA and PDF/UA. Every file is manually verified and screen-reader reviewed rather than auto-tagged, so the ten failures above are actually caught rather than just flagged as a percentage on a scan report. We will check a sample of your real course PDFs at no cost and tell you how many of these ten errors are actually present in your backlog.