We distinguish between two levels of metadata in this document:

  1. Address metadata provides the information needed to address and deliver a package of content from a Source to a Destination
  2. Content metadata provides information about the content package

The content metadata is primarily an issue between Source and Destination, not of transport and delivery. The Design Principles for the Direct Project state that "the design will allow HISPs or intermediaries to fulfill transport needs without access to content or content metadata" in accordance with HIT Policy Committee Privacy and Security Tiger team draft statements.

That being said, the presence of content metadata is a critical element enabling workflow-appropriate content processing. The elements in content metadata can trigger patient identification, workflow processing occasioned by document types, surfacing of the circumstances of content creation, and other key aspects of workflow automation. Such workflow automation is generally required by systems with sophisticated health information technology. This currently tends to be larger institutions, but the benefits of content metadata are not confined to large institutions.

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