2 Rationale

This document defines a recommended form for diagrams representing SNOMED CT concepts.

Historically these diagrams have been created using ad hoc diagramming techniques and styles to express the author's thoughts. Approaches have included borrowing from UML notation and other diagramming standards. However using ad hoc techniques have resulted in

• Confusion and misinterpretation
  • particularly when applying adapted forms of existing standards such as UML where the reader misinterprets the diagram due to their knowledge of the underpinning standard
• Errors and omissions
  • different diagramming techniques require varying levels of detail, some of which do not force the author to think through all aspects of the idea they wish to express
• Inefficiency
  • having a variety of diagrammatic forms requires more effort and time for the reader to interpret
  • creation of a new diagramming form, or selection from many in use and undocumented forms requires more effort and time from the diagram author
  • creation of diagrams by many different people without tooling support such as diagram templates wastes authoring time
• An inconsistent look and feel for SNOMED International documents

In order to address these issues, a diagramming guideline has been created and is presented in this document. The aim of this guideline is to aid a clear, efficient and consistent method of communication for the SNOMED CT community of practice.