How do you write a Vaughn index for documents withheld under FOIA?

A Vaughn index is a document that an agency prepares, usually during FOIA litigation, to justify why it withheld records or portions of records. It takes its name from a federal court decision and exists to solve a basic problem: a requester cannot challenge a withholding they cannot see, and a court cannot review a justification it cannot evaluate. The index bridges that gap by describing each withheld item and tying it to a specific legal basis—without disclosing the protected content itself.

What a Vaughn index must accomplish

A sound index does three things. It identifies each withheld record or redaction with enough specificity to distinguish it from others. It states the exemption claimed for that item. And it explains, in non-conclusory terms, how the exemption actually applies to that particular record. Courts disfavor blanket or boilerplate justifications, so the reasoning should be concrete and document-specific.

How to build one, item by item

Work through the withheld material systematically. For each entry, capture:

• Document identifier: a number or label, plus date, author, recipient, and document type (memo, email, report).
• Description: a neutral summary of subject matter and length or page count, enough to convey context without revealing the protected substance.
• Exemption claimed: the specific statutory exemption invoked.
• Justification: why that exemption fits this record—for example, that it reflects pre-decisional deliberation, contains personal privacy information, or would reveal protected techniques.
• Segregability: a note on whether non-exempt portions were released and, if not, why the material cannot reasonably be segregated.

Many agencies present this as a table or a numbered narrative. The format matters less than the clarity and the link between each fact and each legal claim.

Practical tips

• Be specific but careful: describe enough to justify the withholding without disclosing what the exemption protects.
• Address segregability explicitly; agencies must release reasonably segregable non-exempt portions.
• Keep declarations consistent with the index, since both may be reviewed together.
• Use plain, factual language rather than legal conclusions.

A well-drafted index serves both transparency and defensibility: it lets a requester understand the basis for a denial and gives a reviewing authority a reliable record to assess.

For related guidance, see the FOIA and public records hub.