Introduction
This page is describes changes proposed to the openEHR release 1.0.2 Reference Model (RM) in response to the many lessons learned over the years since its publication. The issues driving the changes are recorded on the Jira SPECPR issue tracker .
ITEM_STRUCTURE & ITEM / CLUSTER / ELEMENT
Needs
- solve the pizza problem - multi-value items
- ITEM_SINGLE, ITEM_LIST etc are not used much in archetyping, and are also not flexible enough because they cannot occur anywhere in a CLUSTER structure
- add a type that is a mixture of CLUSTER and ELEMENT, i.e. has a value and also children, to allow for the fractal nature of data, with a 'summary' value, plus underlying detail
The current data structure models are shown below.
Problems
Problems / irritations with the above models appear to include the following:
- few archetypes use anything but ITEM_TREE because it appears that one 'can never know' if some more detail will be needed later
- TB: but what about things like Apgar, Barthel etc - surely they are linear lists?
- also, it appears that some form of 'table' structure is still needed
- ITEM_TREE, ITEM_LIST etc cannot be nested inside each other arbitrarily.
- the structures complicate the software unnecessarily, without adding much value (this would clearly be true if no/limited use is being made of ITEM_LIST, ITEM_SINGLE)
- archetype paths are made more complex ... MORE INFO REQUIRED - WHAT'S THE PROBLEM?
Below, various simplified models are proposed, each with an impact analysis.
Candidate A - make ITEM_STRUCTURE inherit from CLUSTER
Proposal - Thomas Beale
Status
under construction
Design concept
- Keep ITEM_STRUCTURE and chilren, but just make them a variety of CLUSTER. Impact remaining model as little as possible.
Changes
- ITEM_STRUCTURE now inherits from CLUSTER.
- all static declarations in the remainder of the RM for ITEM_STRUCTURE changed to CLUSTER. In theory they should stay ITEM_STRUCTURE, but the problem is that with no static declarations anywhere for CLUSTER or ITEM, CLUSTER archetypes have no place to go, and the CLUSTER type is not detected by my current 'type closure' detecting algorithm. This should probably be changed.
Impact Analysis
Component
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Impact
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On RM
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On existing archetypes |
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On archetype tooling |
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On existing RM-1.0.2 based software |
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On existing RM 1.0.2 data |
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Candidate B - xxx
Proposal - xx
Status
under construction
Design concept
Changes
Impact Analysis
Component
|
Impact
|
On RM
|
|
On existing archetypes |
|
On archetype tooling |
|
On existing RM-1.0.2 based software |
|
On existing RM 1.0.2 data |
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