Fig. 1From: Defining health data elements under the HL7 development framework for metadata managementFramework of HCDM. HCDM has 6 classes, 15 sub-classes,100 attributes and 100 data types. Each class has several attributes and data types to represent its semantics. The green rectangles represent parent classes and the blue ones represent sub-classes. Hollow arrows represent the inheritance relationship from parent class to child classBack to article page