A privilege log is the document accompanying a discovery production that lists every document withheld for privilege — providing enough information for opposing counsel and the court to evaluate the privilege claim without revealing the protected substance. Federal Rule of Civil Procedure 26(b)(5)(A) requires it; most state rules and international equivalents impose similar obligations. Done well, the privilege log withstands challenges; done poorly, it triggers motion practice and (worst case) waiver findings.
The two privilege log formats
Document-by-document log
The default in most US federal litigation. One row per withheld document, with metadata that lets opposing counsel evaluate the claim:
| Field | Required content |
|---|---|
| Bates number | Unique identifier in the production |
| Date | Document date or transmission date |
| Author | Originating attorney or party |
| Recipients (To / Cc / Bcc) | All recipients including type designation |
| Document type | Email, memo, draft contract, etc. |
| Subject matter | General topic without revealing substance |
| Basis for privilege | Attorney-client / work product / other |
| Description of privilege | Brief explanation of why protected |
A typical large-matter privilege log can contain thousands of entries; one entry per email in a privileged thread (not one per thread).
Categorical (or “by category”) log
Increasingly used in high-volume cases by court order or party agreement. Documents are grouped into categories (e.g., “Communications between Lead Litigation Counsel and General Counsel re: Matter X, dated 2024-2025”) with one log entry per category covering counts of documents.
Categorical logs reduce log generation cost dramatically — but require court or opposing counsel agreement, and require sufficient detail per category to support meaningful evaluation.
What a good privilege log entry looks like
Bad: Email re: Legal advice. Privileged.
Better: Email from outside counsel to General Counsel re: assessment of indemnification claim under Section 8.3 of the Master Services Agreement. Attorney-client privileged communication seeking and providing legal advice.
The second entry tells opposing counsel:
- The communication was attorney-to-client (privilege element)
- The subject was legal advice (privilege element)
- The specific subject matter without revealing substance
- The reasonable basis for the claim
Common challenges to privilege logs
Opposing counsel typically challenges:
- Vague descriptions. “Re: legal advice” without subject matter
- Inflated logs. Documents on the log that aren’t actually privileged (business communications, fact-only content)
- Missing entries. Documents that should be on the log but aren’t (suggesting inadvertent production or under-claim)
- Inconsistent treatment. Same email withheld in one custodian’s log but produced in another’s
- Improper “privilege” assertions. Materials that aren’t actually privileged under applicable law (in-house business advice, attorney’s calendar entries)
Each challenge can result in motion to compel, in camera review, or ultimate waiver findings.
How to operationalize
- Privilege log template at matter intake. Define the format, fields, and granularity standard before review begins. Mid-matter format changes are expensive.
- Auto-populate from review tool metadata. Relativity, Everlaw, DISCO all auto-populate Bates, date, parties, and document type from review tags. Reviewer adds subject matter and basis.
- AI-assisted subject matter generation. LLMs draft the subject-matter description from the redacted document content; attorney finalizes. Major cost reduction at scale.
- Categorical agreement with opposing counsel where possible. For high-volume cases, propose categorical log structure early. Most opposing counsel will agree if the categories are sufficiently detailed.
- Final attorney review. Before producing the log, an attorney reviews each entry for sufficiency, consistency, and accuracy. Sample at minimum 10% of entries; review 100% of entries with novel privilege bases.
- Audit log of every entry’s history. Who tagged it as privileged, who reviewed it, who finalized the entry. Critical for defending against post-hoc challenges.
Common pitfalls
- Boilerplate descriptions. Identical descriptions across thousands of entries draw automatic challenges. Each entry needs document-specific subject matter.
- Treating drafts inconsistently. Drafts often have different privilege analysis than finals; ensure drafts marked privileged are evaluated on their own merits.
- Ignoring metadata. A log entry that excludes the recipients makes evaluation impossible; opposing counsel will challenge.
- Over-claiming with attorney cc. An attorney cc’d on a business communication doesn’t automatically privilege the communication. Over-claiming attracts challenges.
- Forgetting work-product separately. Work product and attorney-client privilege are separate doctrines with separate elements; logs should specify which (sometimes both) applies.
Related
- Privilege review — the upstream review process the log documents
- eDiscovery — broader workflow privilege logging fits inside
- Redaction workflows — adjacent for partially-privileged documents