1. HL7 Version 3 Process and Tools - Charlie McCay
12 December 2003
Introduction to HL7
Charlie McCay

2. Charlie McCay Interest in Clear and Testable specifications
Co-Chair HL7 XML Special Interest Group
Chair HL7UK Technical Committee
XML input to these specifications:
RACPC+PROFESS – CEN data-sets
GP2GP – early adopter for HL7V3
ETP – Electronic Transfer of Prescriptions Pilot
DMSP Clinical pathways (HL7v3)

3. How HL7 works HL7.org and HL7UK… Products… Organisation… Meetings…
Ballots…

4. HL7.org and HL7UK Membership organisations
Both aim to provide standards that support Clinical Information System Interoperability
HL7UK does this in a UK context

5. Products Specifications Methods for developing specifications
V2, V3, CDA, Arden, CCOW, …
Informative, Normative or Reference
Methods for developing specifications
MDF, HDF, …

6. Organisation ANSI, ISO, CEN TCs, SIGs and others
Technical Committees
Special Interest Groups
HL7.org, and the affiliates

7. HL7.org Meetings Working Group Meetings Harmonisation Conference calls
Three meetings a year, 400 attendees
Committee work and tutorials
Harmonisation
Three times a year, 20 attendees
Conference calls
Mailing lists

8. HL7UK meetings 6 technical meetings a year, 20-30 attendees
Networking
Reporting on UK HL7 projects
Planning UK activity in HL7.org
detailed review
UK conference
HC200x Stand and demonstrations

9. Ballots Central and Affiliate Committee and Membership
Joining ballot pools, and meaning of votes
Resolution of negatives

10. Semantics and Technology
“Semantics” is the definition of the data items that are permitted in the message
“Technology” is what is used to transmit that meaning between systems
Hl7v3 is semantics, XML is technology

11. Skills Reuse XML used for more than just EDI
Component interfaces
User interface
Printed Document formatting
Temporary and persistent Data storage
Semantics are not just used in interfaces
Reporting engines
System architecture
Requirements gathering

12. Training and Skills EDI needs experienced developers
XML skills can be developed elsewhere
Parser writing
Not need widely in Clinical applications
Error prone
EDI can become a trap for good developers

13. Validation at Source Schemas, DTDs, and black boxes
Keep your own dirty laundry
Avoid doing free testing for other suppliers
Identify who is responsible for errors
Machine readable specifications
Taken further in V3

14. Are the Schemas normative
Do I have to use the Schema?…
What is normative is the definition of the set of valid instances
DTD / Schema used for:
Description
Validation
Validation takes time
Diagnostic and runtime validation

15. Is Schema validation enough?
No – Rules the schema does not check
Co-occurrence constraints
Contingencies on facts beyond the message
Orchestration of the messages
No – Schema validators get better

16. Tools Visio Tools Schema generator Message Viewer – xClinView
Message Documentation Editor
Schema processors, rsXMLtest
XML IDE -- XML Spy