Introduction and Background
What is METS?
The Metadata Encoding and Transmission Standard (METS) is a data encoding and transmission specification, expressed in XML, that provides the means to convey the metadata necessary for both the management of digital objects within a repository and the exchange of such objects between repositories (or between repositories and their users). This common object format was designed to enable the sharing of efforts in the development of information management tools/services and to facilitate the interoperable exchange of digital materials between institutions (including vendors). The METS XML schema was created in 2001 under the sponsorship of the Digital Library Federation (DLF), is maintained by the Library of Congress, and is governed by the METS Editorial Board. In 2023, the revisited version 2 was released.
What problem is METS trying to solve?
Many institutions in the digital arena are finding it at least desirable, if not necessary, to maintain metadata about the digital objects they create and/or preserve. As the number and complexity of these digital objects increase, institutions are finding that the metadata needed for successful management, access, and use is both more extensive and different from the metadata used to manage, access, and use their other collections. For example, many institutions find it necessary to preserve structural metadata that describes, anchors, and organizes the components of a digital object so that the integrity of the digital object can be maintained even if its components are stored in different locations. And when a repository of digital objects intends to share metadata about a digital object, or the object itself, with another repository or with a tool intended to render the object, the use of a common data transfer syntax between repositories and between tools greatly improves the ease and efficiency with which the transactions can occur. METS was created and designed to provide a relatively simple format for these types of activities during the lifecycle of the digital object.
How is METS maintained?
The METS Editorial Board maintains editorial control of METS, its XML Schema, the METS Profile XML Schema, and the official METS documentation. In addition, the Board promotes the use of the standard, maintains a registry of METS profiles, and endorses best practices for using METS as they emerge.
The METS Editorial Board is a volunteer group selected from the international METS community. Board members typically represent institutions that have or plan to implement METS, but also come from various sectors of the information creation and delivery community including academic research libraries, local and national archives, museums, national libraries, governmental and non-governmental organizations, and vendors. The current membership of the Board can be found on the METS website.
The Library of Congress maintains METS by hosting the website and providing other invaluable support and services.
Who is the METS community?
METS use has grown steadily since 2001. To the best of our knowledge, many in the METS community are university libraries, archives, or museums, but there is no way to know of all METS implementations. Those institutions that have chosen to register their implementation can be found on the METS Implementation Registry.
How can I find out more about METS?
The METS website, maintained by the Library of Congress, is a good place to start for those interested in learning more about METS. The current and previous versions of the METS schema and related documentation, including a METS Overview and Tutorial in a number of languages, can be found on the METS website. Additional documents, examples, and technical information can be found on the METS GitHub page.
Technical questions about using METS and other questions can be directed to the METS listserv.