The Metadata Encoding and Transmission Standard (METS) was initially developed for the Digital Library Federation by Jerome McDonough. Complicated digital objects such as books require structural metadata in order to relate the pages and chapters to one another, as well as to the whole. Technical metadata is needed to inform scholars of how accurate a representation the digital object is, and also to enable the library to periodically refresh and migrate the data to ensure durability. In addition, a standardized schema that encompassed all the preservation and use needs of the digital object was desirable for share-ability, particularly within the proposed Open Archival Information System (OAIS) Reference Model.
The METS schema is a standard for encoding descriptive, administrative, and structural metadata regarding objects within a digital library, expressed using the XML schema language of the World Wide Web Consortium. The standard is maintained in the Network Development and MARC Standards Office of the Library of Congress, and is being developed as an initiative of the Digital Library Federation.