At a glance
Define the collection first, retrieve permitted files, establish positive counts and group confirmed identical bytes. Report both the sum across counted URLs and the sum once per identical-file group. Unknown counts and unseen scope remain separate limitations rather than zero-page contributions.
A and B have identical bytes; C is different; D is uncounted. Digests are represented by illustrative group labels, not real hashes.
| URL | Identity group | Verified pages | Result |
|---|---|---|---|
| example.org/a.pdf | G1 | 10 | Counted |
| example.org/b.pdf | G1 | 10 | Counted duplicate |
| example.org/c.pdf | G2 | 2 | Counted |
| example.org/d.pdf | Unknown | Unknown | Password required |
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Name the measures before reporting them
A discovered PDF URL is a candidate retrieval location. A counted PDF URL has a verified positive page count in the saved attempt. An identical-file group contains retrieved PDFs with matching byte identity. Uncounted URLs retain a reason and no claimed page contribution.
| Measure | Rule | Use |
|---|---|---|
| Discovered PDF URLs | All recorded PDF candidates in scope | Size of the known link ledger |
| Counted URLs | Candidates with verified counts | Counting completion denominator relationship |
| Confirmed URL pages | Sum pages for every counted URL | Public link footprint |
| Confirmed unique pages | Sum once per counted identical-file group | Source work once per identity |
| Unknown counts | Candidates lacking verified counts | Explicit follow-up queue |
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Keep the arithmetic reproducible
In the example, URL pages are 10 + 10 + 2 = 22. Unique pages are 10 + 2 = 12. There are four discovered URLs, three counted URLs, two confirmed identity groups and one uncounted URL. Counting completion is 3 ÷ 4 = 75% for this ledger only.
Do not infer D’s size from the other files. Do not label 75% as website coverage: the collection may omit unlinked or unreachable PDFs. An aggregate should travel with the source date, identity rule, retrieval scope, count method and unresolved outcomes.
- URL pages = sum of verified counts across counted URLs.
- Unique pages = sum of verified counts once per identical-byte group.
- Uncounted URLs = discovered URLs minus counted URLs, for the same saved ledger.
- Counting completion = counted URLs / discovered URLs, when the denominator is positive.
Distinguish verification from repair and review
DocAccessible uses strict structural counting, with a bounded eligible fallback that requires a consistent page tree and an independent reader’s agreement. Recovered results retain that label. It does not rewrite the original source or infer a count when verification is incomplete.
Byte-identity grouping does not merge visually similar re-exports. A count does not validate tag quality, content accuracy, signatures or conformance. Coverage reporting is another evidence layer: failed website requests may conceal additional files, but their number and page count remain unknown.
Sources and scope
Methods, worksheets and illustrative examples are DocAccessible editorial contributions. These references support the technical or product details described above. W3C techniques are informative guidance; they are not a certification scheme.
- DocAccessible PDF inventory
The counting workflow, report options and purchase boundary.
- QPDF: PDF inspection and exit status
Structural inspection, page-count options and warning versus error outcomes.
- Python hashlib documentation
SHA-256 hashing of file bytes.
Written by the DocAccessible team under our editorial policy. Suggest a correction if a source or product detail needs updating.
See the evidence in a working example
Explore the public sample inventory report to try its table, full-screen view and missing-count reasons. The downloadable counting fixture check records what the local counter returned for seven self-authored inputs, with hashes and explicit limits.