Redaction Taxonomy
A practical coding scheme for Freedom of Information (FOI) redaction analysis
GlassCase Redaction Taxonomy v0.2 is a practical coding scheme for analysing FOI releases across Australian jurisdictions. It is designed for comparative analysis of redaction patterns and decision quality, not as a substitute for statutory exemption categories.
Optional statutory mapping is provided for Commonwealth FOI to support jurisdiction-specific reporting (see Statutory Mapping below).
Use it to code FOI redactions, compare patterns across agencies, and flag decision-quality issues for review.
How to cite (APA 7): GlassCase. (2025, December). Redaction Taxonomy (Version 0.2). https://glasscase.org/redaction-taxonomy.html
CSV coding sheet available: Download CSV
Substantive Categories
- A1 Direct identifiers: name, address, phone, email, ID numbers
- A2 Indirect identifiers: role + small team context, unique events, rare attributes
- A3 Third-party spill: unrelated people caught in the record
- B1 Physical safety: threats, location risks
- B2 System security: credentials, network details, security controls
- B3 Operational security: routines, response playbooks
- C1 Supplied in confidence: externally provided information
- C2 Business or commercial confidence: procurement, pricing, negotiations
- C3 Inter-agency confidentiality: referral pathways, sharing constraints
- D1 Drafting and iteration: working drafts, tracked changes
- D2 Deliberation material: options, advice, internal debate
- D3 Legal material: advice, privilege claims, litigation posture
- E1 Ongoing investigations: integrity bodies, HR processes, audits
- E2 Law enforcement overlap: offences, intelligence, methods
Pattern Flags
These are not reasons for redaction—they're signals of potential decision quality issues worth tracking.
Job titles and dates removed even where identity risk is already eliminated.
The same person's role is disclosed in one email chain but redacted in another.
"Could identify an individual" asserted with no description of what combination creates the risk.
Privacy invoked to remove operational embarrassment—e.g., redacting process errors that do not identify anyone.
Entire paragraphs blacked out where only one sentence contains sensitive detail.
Statutory Mapping (Commonwealth)
FOI Act 1982 (Cth) — Section Reference
This table maps taxonomy categories to the most commonly invoked exemption sections. The FOI Act distinguishes between absolute exemptions (Division 2, Part IV) and conditional exemptions (Division 3, Part IV). Conditional exemptions require a public interest test under s 11A(5) and s 11B.
| Category | Typical FOI Act Section(s) | Notes |
|---|---|---|
| A — Personal Privacy | s 47F |
Conditional; requires "unreasonable disclosure" test + public interest balance |
| B — Safety & Security | s 33, s 37 |
Absolute exemptions for national security (s 33) and law enforcement/public safety (s 37) |
| C — Confidentiality | s 45, s 47G |
Breach of confidence (s 45, absolute); business affairs (s 47G, conditional) |
| D — Decision-process | s 47C, s 42 |
Deliberative processes (s 47C, conditional); legal professional privilege (s 42, absolute) |
| E — Enforcement | s 37, s 47E |
Law enforcement (s 37); operations of agencies (s 47E, conditional) |
Key procedural sections
Redaction logic in practice: apply an exemption (Part IV), apply the public interest test for conditional exemptions (s 11A(5), s 11B), then release an edited copy where reasonably practicable (s 22), with reasons (s 26).
s 11A — Mandatory access rule. Conditionally exempt documents must be released unless access would be "contrary to the public interest."
s 11B — Public interest factors. Lists factors favouring access (e.g., oversight of expenditure, informing public debate) and irrelevant factors that must not be considered (e.g., embarrassment to government).
s 22 — Access to edited copies with exempt matter deleted. Agencies must provide edited copies where reasonably practicable, with notice of grounds for deletion.
s 26 — Reasons for decision. Refusals must state findings on material questions of fact and reasons, including public interest factors for conditional exemptions.
s 47 — Trade secrets and commercially valuable information. Commonly invoked alongside s 47G for commercial matters; s 47 is an absolute exemption while s 47G is conditional.
Victoria mapping: State jurisdiction adapter coming in a future release.
Worked Example
Coding a release pack in 6 minutes
Illustrative example. Synthetic ministerial briefing package (12 pages, partial release) modelled on typical disclosure log material.
| Page | Redaction | Stated Reason | Code | Flag |
|---|---|---|---|---|
| 1 | Drafter name, email | s 47F personal privacy | A1 | |
| 3 | Entire recommendation paragraph | s 47C deliberative | D2 | P5 |
| 4 | "Senior policy officer" title | s 47F personal privacy | A2 | P1 |
| 7 | Contractor pricing schedule | s 47G business affairs | C2 | |
| 9 | Drafter email (same as p.1) | s 47F personal privacy | A1 | |
| 11 | Name disclosed in footer | not stated | P2 |
How to Use This Taxonomy
- Audit: Code releases to compare patterns across agencies or time. Identify which categories cluster, which flags recur, and where practice diverges from OAIC guidance or s 26 decision-letter obligations.
- Review: Use flags to identify over-redaction or inconsistency for internal review requests or OAIC IC review preparation. Flag P3 (mosaic risk without explanation) and P4 (category drift) are particularly useful for challenging weak decisions.
This taxonomy is also suitable for training FOI officers and law students—it provides a shared vocabulary for discussing redaction practice across jurisdictions.
Version History
v0.2 (December 2025): Added FOI Redaction Logic Visualiser and improved mobile usability (embedded visualiser + scrollable tables).
v0.1 (December 2025): Initial release. Commonwealth FOI Act mapping only.