Principles for the Discovery of Electronically Stored Information in Civil Cases
Appendix 3: Metadata Reference Guide
Metadata is information that helps us use and make sense of other information. More
particularly, metadata is information, typically stored electronically, that describes the
characteristics, origins, usage, structure, alteration, and validity of other electronically stored
information (“ESI”). Metadata occurs in many forms within and without digital files. Some is
supplied by the user, but most metadata is generated by systems and software.
Some define metadata simply as “data about data,” where others characterize metadata as data
that is not user-generated but is created by a computer system or application to keep track of a
file’s attributes. However, even user-generated data may qualify as metadata. For example, a
Bates number is metadata, although assigned by counsel.
Because metadata is defined so broadly, a blanket request for the production of metadata may be
unhelpful. The metadata values associated with a particular file or information item vary
according to the nature of the item and its use. For example, the relevant metadata from a word
processed document differs from e-mail metadata and from metadata pertinent to a database.
Metadata is unlike almost any other discoverable information because its import may flow from
its probative value as relevant evidence, its utility in functionally abetting the searching, sorting,
and interpretation of ESI, or both. If the origin, use, distribution, destruction, or integrity of
electronic evidence is at issue, the relevant “digital DNA” of metadata is probative evidence that
should be preserved and produced. Likewise, if the metadata materially facilitates the searching,
sorting, and management of ESI, it should be preserved and produced for its utility.
Absent a specific agreement between parties or instruction from the Court as to the form or
forms of production, parties typically produce information in the form or forms the information
is ordinarily maintained or in some other reasonably usable form. In determining what form or
forms to produce data, a producing party should take into account the need to make metadata as
accessible both to display and to search, for the receiving party as it is to the producing party,
where appropriate and necessary, after consideration of proportionality factors outlined in
Principle 1.03.
Metadata can be generally categorized as System Metadata or Application Metadata.
System Metadata reflects context, being information about a file that is not embedded within the
file it describes, but is stored externally by the computer’s file management system, which uses
system metadata to track file locations and store demographics about each file, e.g., file name,
size, creation, modification, and usage. System metadata may be crucial to electronic discovery
because so much of our ability to identify, find, sort, and cull information depends on its system
metadata values. For example, system metadata helps identify the custodians of files, when files
were created or altered, and the folders in which they were stored.