Openness comes as a PDF: what format says about how usable this data really is
Two things become visible once you look past individual releases to the shape of the dataset as a whole: what format the actual data arrives in, and which part of the law gets reached for to stop it arriving at all. Neither is uniform.
PDF is the format of UK government transparency
Across every attachment we've archived and analysed - more than 35,000 files - 86% are PDFs. Genuinely machine-readable CSV, the format you could drop straight into a spreadsheet or a script without a conversion step, is 2.5%. Word documents and spreadsheets make up most of the rest - together over a tenth of everything released.
This matters more for health data than most: a table of waiting times, incident counts, or medicines data trapped in a scanned or exported PDF has technically satisfied a disclosure obligation while remaining something a researcher has to manually retype before they can do anything with it.
Which exemption gets used tracks the subject, not just the requester
Cross-referencing exemption citations against our topic tags shows real variation by subject:
| Topic | Security / law enforcement exemptions | Commercial confidentiality | "Not held" |
|---|---|---|---|
| Hospital Trusts & Estates | 30.0% | 13.8% | 16.3% |
| Medicines & Regulation | 8.3% | 22.9% | 26.8% |
| Mental Health Services | 7.4% | 3.7% | 37.0% |
The Hospital Trusts & Estates figure is the most surprising one here - a healthcare topic showing the highest security/law-enforcement exemption rate of anything we've measured, in either niche tracker. Read alongside "Estates" in the topic name, the likely explanation is physical site security - CCTV coverage, security contractor arrangements, access control at hospital sites - rather than clinical matters, though our sample (80 releases) is small enough that this deserves more digging before we'd call it settled. Medicines & Regulation leans hardest on commercial confidentiality, plausibly reflecting drug licensing and clinical trial data genuinely covered by commercial agreements. Mental Health Services has the highest "not held" rate of the three by a wide margin - worth reading alongside our MHRA piece and our note on why most individual trusts are absent from GOV.UK's own feed in the first place, since a body simply not holding the requested data is a different failure mode to one actively blocking it.
Reading this responsibly
Format figures cover every attachment we've archived to date, regardless of topic. Exemption figures are keyword-presence rates - a document mentioning a section number isn't necessarily one where that section was the operative reason for withholding - and these topic samples (80, 157, and 27 documents respectively) are small enough that we'd treat the specific percentages as suggestive rather than final.