Metadata is the description (preferably standardized) of an information-bearing object (IBO) (Kim, 2008). Meta refers ‘to data about data’. While metadata has application in many fields, especially library science, in medicine it generally refers to electronic information about a given resource.
Most references refer to three types of metadata (National Information Standards Association, 2004):
is used to describe an IBO for identification, searching and retrieval. An example of metadata used in this manner is the system used by PubMed to describe articles or books which can then be used for search and retrieval. In this case the metadata is referred to as ‘field descriptions’ and ‘tags’ (Search Field Descriptions and Tags, 2009). Within medical records, diseases can be described using the ICD-10 codes which are a commonly used descriptive metadata (2009 ICD-10-CM, 2009).
is used to describe how different parts of a resource relate to each other. In a book this would be the table of contents, chapters, and pages. Within a journal article this would be the pages, figures, etc. In a medical record it might describe the relationship between the chief complaint within the history and physical exam or the list of studies that are obtained during a patient encounter. This structural metadata is used for navigation through a compound resource.
is used to describe a resource for processing and management. The designation of the file type is an example. Privacy and security designations for handling the medical record are considered administrative metadata. The Health Insurance Portability and Accountability Act (HIPAA) is active in standardizing practice for EHRs as relates to privacy and security. This type of metadata is also essential for the archiving/preservation of an IBO and describing property rights.
The point of developing metadata descriptions/systems is to improve interoperability within and between systems and federated organizations. This implies the need for standardization of the metadata which can occur at different levels of functionality; for one discussion of this issue see the Metadata Basics  at Dublin Core Initiative (Dublin Core Metadata Initiative, 2009). For interoperability to be achieved there must be agreement upon the structure specifications by stakeholders at many levels of detail: such examples are spelled out in the DCMI terms but include character encoding (ASCII, Unicode, etc), language, message structure (DICOM and HL7), controlled vocabularies, and formatting. If these areas are standardized and agreed upon then interoperability can be achieved. Much of the development of standardized metadata has been commercially driven in recent years by the development of the Web, the Resource Description Format (RDF), demand for search capabilities and the generation of the ==linked data cloud==. Healthcare metadata standardization has lagged for many reasons but clearly interoperability is achievable with constraints unique to healthcare if and when the incentive is present for all parties to agree to the metadata standards for interoperability.
2009 ICD-10-CM. (2009, November 20). Retrieved November 22, 2009, from Centers for Medicare and Medicaid Services: http://www.cms.hhs.gov/ICD10/02m_2009_ICD_10_CM.asp#TopOfPage
DCMI Usage Board. (2008, January 14). DCMI Metadata Terms. Retrieved November 22, 2009, from Dublin Core Metadata Initiative: http://dublincore.org/documents/dcmi-terms/
Dublin Core Metadata Initiative. (2008, January 14). Retrieved November 22, 2009, from Dublin Core Metadata Element Set, Version 1.1: http://dublincore.org/documents/dces/
Dublin Core Metadata Initiatve. (2009). Retrieved November 22, 2009, from Metadata Basics: http://dublincore.org/metadata-basics/
Kim, G. (2008). Metadata in Medicine. Retrieved November 24, 2009, from MELD: http://meld.medbiq.org/primers/metadata_in_medicine_kim.htm
National Information Standards Association. (2004). Understanding Metadata. Retrieved November 22, 2009, from NISO: http://www.niso.org/publications/press/UnderstandingMetadata.pdf
Search Field Descriptions and Tags. (2009). Retrieved November 22, 2009, from PubMed Help: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=helppubmed&part=pubmedhelp#pubmedhelp.Search_Field_Descrip
Submitted by (Christine Schlichting)