n.information about data that promotes discovery, structures data objects, and supports the administration and preservation of recordsDollar 1992, 87Metadata. Data describing data and data systems that may include the structure of databases, their characteristics, location, and usage.Michelson and Rothenberg 1992, 294But metadata, data about data that archivists typically collect about a body of records, may serve as the basis for a supplementary descriptive system to complement existing bibliographic information.McDonald 1995, 151Consequently, while existing standards for automated repositories, such as the IRDS standard and the de facto repository standards that could emerge from the current efforts of IBM, Digital Equipment Corp., and others, will concentrate on the management of information about information (also known as metadata), future repository “standards” will manage information about objects—processes and related data as single entities—and about the business functions to which they relate.Lynch 2000, 34We have an object and a collection of assertions about it. The assertions may be internal, as in a claim of authorship or date and place of publication on the title page of a book, or external, represented in metadata that accompany the object, perhaps provided by third parties. We want to ask questions about the integrity of the object: Has the object been changed since its creation, and, if so, has this altered the fundamental essence of the object? (This can include asking these questions about accompanying assertions, either embedded in the object or embodied in accompanying metadata).Bergeron 2002, 9Metadata includes descriptive summaries and high-level categorization of data and information. Knowledge is information that is organized, synthesized, or summarized to enhance comprehension, awareness, or understanding. That is, knowledge is a combination and an awareness of the context in which the data can be successfully applied. Although the concept of data is roughly equivalent to metadata, unlike data, information, or metadata, knowledge implies a human—rather than computer—host.Puglia, Reed, and Rhodes 2004, 6Metadata makes possible several key functions—the identification, management, access, use, and preservation of a digital resource—and is therefore directly associated with most of the steps in a digital imaging project workflow: file naming, capture, processing, quality control, production tracking, search and retrieval design, storage, and long-term management.Schaefer and Bunde 2013, 48Metadata differs from traditional library cataloging or archival description; while it includes library catalog records and archival descriptive records, it also extends beyond the traditional formats of books or records and often serves as data about digital resources,which require additional information for their care and management.Zhang and Mauney 2013, 182The movement to digitization generates digital objects with associated metadata. As a result, traditional archival materials are supplied with item-level description and metadata when turned into digital objects, a new element in digital archival representation that archivists are challenged to incorporate into the traditional archival description.Gilliland 2014a, 111Today, metadata refers to anything that is said about any information object, at any level of granularity, and at any point in its life. In archival terms, therefore, metadata encompasses not only representations of the content, but also descriptions and traces of the various contexts of records and other archival materials.NARA 2015Simply put, metadata are elements of information that answer the questions ‘who, what, where, when, and why’ regarding electronic records. Metadata elements provide administrative, descriptive, and technical information that describe the structure and content of electronic records. Metadata elements also provide contextual information that explains how electronic records were created, used, managed, and maintained prior to their transfer to NARA, and how they are related to other records. This information enables NARA to appropriately manage, preserve, and provide access to electronic records for as long as they are needed.Riley 2017, 6The cultural heritage community distinguishes descriptive metadata from other types. Administrative metadata is an umbrella term referring to the information needed to manage a resource or that relates to its creation. Within the administrative metadata sphere is technical metadata, information about digital files necessary to decode and render them, such as file type; preservation metadata supporting the long-term management and future migration or emulation of digital files, for example, a checksum or hash; and rights metadata, such as a Creative Commons license, which details the intellectual property rights attached to the content. Descriptive and administrative metadata are considered distinct from structural metadata, which describes the relationships of parts of resources to one another; examples include pages in a sequence, a table of contents with pointers to the beginnings of milestone sections, and connecting different resolutions or bit depth representations of identical content.
Metadata may be embedded or external. It may be applied at a variety of levels of granularity and during different periods in the life cycle of data. It is typically demarcated and standardized, and it often provides context.