§ Reference · Glossary · Reviewed September 2026
The vocabulary of disclosure, in both jurisdictions.
English practice says eDisclosure, American practice says eDiscovery, and a surprising number of arguments are really translation problems. Every term below is defined plainly, with the US equivalent given where the two vocabularies diverge.
Ref · E-D · 2026 · §GLSClass · ConfidentialJuris · England & WalesStatus · Active
ReferenceProcedure
- eDisclosureUS: eDiscovery
- The process of identifying, preserving, collecting, processing, reviewing and producing electronically stored information in litigation, arbitration or a regulatory investigation. England and Wales uses disclosure; the United States uses discovery. The activity is the same.
- DisclosureUS: Production
- The step at which documents are made available to the other side. Under CPR Part 31 and PD 57AD a party discloses a document by stating that it exists or has existed; inspection follows. In US practice the equivalent delivery of documents is called production.
- Practice Direction 57AD
- The disclosure regime for the Business and Property Courts of England and Wales, in force since October 2022 and replacing the Disclosure Pilot. It requires Initial Disclosure, a Disclosure Review Document and a choice between Extended Disclosure Models A to E.
- Disclosure Review DocumentUS: ESI protocol
- The DRD is the document in which parties under PD 57AD record the issues for disclosure, the models proposed, the data sources, custodians, date ranges, search terms and the estimated costs. The nearest US equivalent is a negotiated ESI protocol.
- Extended Disclosure Models A to E
- The five models available under PD 57AD: A, no search-based disclosure beyond known adverse documents; B, limited disclosure; C, request-led search-based disclosure; D, narrow search-based disclosure with express duties; E, wide search-based disclosure including train-of-enquiry documents.
- Known adverse documents
- Documents a party is actually aware of that contradict or materially damage its own case, or support another party's case. They must be disclosed under PD 57AD regardless of the model ordered.
- Legal holdUS: Litigation hold
- A documented instruction suspending routine deletion of potentially relevant material once litigation or an investigation is reasonably in contemplation. In England and Wales the duty to preserve arises when proceedings are contemplated; in the United States it arises when litigation is reasonably anticipated.
- Spoliation
- The loss, destruction or material alteration of evidence after a preservation duty arises. In the United States it is addressed by FRCP 37(e); in England and Wales the court may draw adverse inferences, strike out a statement of case, or impose costs consequences.
- CPR Part 35
- The rule governing expert evidence in civil proceedings in England and Wales. The expert's overriding duty is to the court, the report must state the substance of all material instructions, and permission is required to rely on expert evidence.
- CrimPR Part 19
- The equivalent rule for expert evidence in criminal proceedings in England and Wales, including the duty to the court, disclosure of anything that might detract from the expert's credibility, and the requirements for an expert report.
- Section 1782
- 28 U.S.C. §1782, the United States statute allowing a federal district court to order discovery located in the US for use in a foreign proceeding. It is often used in parallel with English proceedings; a mirror route for US parties seeking English evidence is a letter of request under the Hague Evidence Convention.
- Hague Evidence Convention
- The 1970 Convention on the Taking of Evidence Abroad in Civil or Commercial Matters, the formal route by which a foreign court asks the English court to take evidence from a person in England and Wales.
Data and technical
- Electronically stored information
- ESI. Any information created, manipulated, communicated, stored or best used in digital form: email, chat, documents, databases, mobile data, cloud platforms, metadata and system artefacts.
- Custodian
- An individual, or sometimes a system, holding potentially relevant data. Custodian selection is the single largest determinant of collected volume and therefore of cost.
- Forensic image
- A bit-for-bit copy of a storage device or logical container, hash-verified so that the copy can be shown to be identical to the source. The standard basis for defensible examination of a device.
- Hash value
- A fixed-length fingerprint of a file or disk, typically MD5 or SHA-256. Used to verify that evidence has not changed, to de-duplicate across custodians, and to identify known files.
- Chain of custody
- The documented, unbroken record of who held evidence, when, and what was done to it, from seizure or collection through to production. Without it, authenticity is arguable.
- Metadata
- Data describing a document: author, dates, path, recipients, device identifiers, GPS, revision history. Frequently the most probative material in a disclosure exercise, and easily destroyed by careless copying.
- De-duplication
- Removing identical copies of a document so it is reviewed once. Global de-duplication works across all custodians; custodian-level de-duplication works within each, and produces a larger review set.
- Email threading
- Grouping an email conversation so that only the most inclusive message in each branch needs review, with earlier messages suppressed as wholly contained. Routinely removes a fifth to a third of an email review set.
- Near-duplicate detection
- Identifying documents that are textually similar but not identical, such as successive drafts, so they are reviewed together and coded consistently.
- Technology-assisted reviewUS: Predictive coding
- TAR. Machine learning applied to prioritise or classify documents for relevance from human decisions on a training or continuously updated set. TAR 1.0 uses a trained model applied to the remainder; TAR 2.0 uses continuous active learning. Endorsed in England and Wales since Pyrrho Investments v MWB Property (2016).
- Early case assessment
- ECA. Analysis of collected data before full review to test volumes, search terms, date ranges and themes, so that scope, budget and strategy can be set on evidence rather than assumption.
- Search terms
- Keyword and proximity queries agreed between the parties to identify potentially disclosable documents. Under PD 57AD the terms and their results are recorded in the DRD, and disproportionate terms can be challenged.
- Load file
- The structured file, commonly DAT, OPT or a Relativity-compatible format, that carries metadata and image references so a production can be loaded into the receiving party's review platform.
- Bates numbering
- Sequential, unique identifiers stamped on produced pages or documents. UK productions more often use a document control number, but the function is identical: an unambiguous reference for every page.
- Privilege log
- A schedule of documents withheld from inspection on grounds of legal professional privilege, describing each sufficiently to allow the claim to be tested without revealing the privileged content.
- Redaction
- Permanent removal of privileged, irrelevant-sensitive or personal content from a produced document. Burned into the image, with the underlying text removed rather than merely hidden.
Standards and compliance
- EDRM
- The Electronic Discovery Reference Model, the nine-stage framework (information governance through presentation) used across the industry to describe the discovery lifecycle.
- NPCC guidelines
- The National Police Chiefs' Council guidelines on digital evidence in England and Wales, the recognised principles for handling digital evidence so that it remains admissible, including that data must not be changed and that an audit trail must be kept.
- ISO/IEC 27037
- The international standard for identification, collection, acquisition and preservation of digital evidence. ISO/IEC 27041 addresses assurance of investigation methods; ISO/IEC 17025 is the laboratory competence standard that forensic units align to.
- UK GDPR and DPA 2018
- The UK data protection regime. Relevant to disclosure through lawful basis for processing, data minimisation, the treatment of special category data, and the mechanisms required before personal data is transferred outside the UK.
- IDTA and UK Addendum
- The International Data Transfer Agreement and the UK Addendum to the EU Standard Contractual Clauses, the two principal mechanisms for lawfully transferring UK personal data to a country without an adequacy decision, including the United States where the Data Bridge does not apply.
- FRCP 26, 34 and 37
- The United States Federal Rules of Civil Procedure governing the scope and proportionality of discovery, requests for production of ESI, and sanctions for failure to preserve. Rule 502 addresses inadvertent disclosure of privileged material.
- Sedona Principles
- The leading US commentary on best practice in electronic document production, widely cited on proportionality, cooperation and the treatment of metadata and forms of production.
- Clawback agreement
- An agreement, often reflected in a court order, that inadvertent production of privileged material does not waive privilege and that the document must be returned or destroyed on notice.
Instruct the practice
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