Hi Richard,
the default setting when adding a Text datatype in an archetype is 'Free
text or coding'. This can be further constrained as an internal codeset
or bound to terminology within the archetype, as required.
I totally agree that in a majority of cases the 'Free text or coded'
option is ideal. After all the archetype is 'a maximal data set for a
UNIVERSAL USE CASE' - this gives us the most flexibility ranging from
free text entry through to coding at runtime.
If left as 'free text or coded' then the element can be further
constrained by binding to a terminology subset in the template - one
that is relevant and meaningful for the use case. This is in
increasingly common use and a key consideration in active modelling at
present.
The internal codes are useful where you need more structure than free
text, but a terminology subset cannot meet the needs for structured data
capture, and this is the situation in the BP archetype.
The large number of clinicians who have looked at the BP archetype over
the years have not had any problem with the internal code list of
positions - so lying, sitting, standing and reclining seem to make
clinical sense to them. Now I am not a Snomed expert at all, but when
browsing for body position within Snomed there does not seem to be a
consistent way to represent these 4 terms. Yes, by all means bind the
SCT term 33586001 to the sitting value (and this is possible in the
Archetype Editor via the Terminology tab). And you may find acceptable
ones for standing and lying, although not so clear to me. But reclining
appears to be absent on my searches, and this is probably the default
value that is desired for most BP readings in an inpatient hospital
situation.
So internal codes are providing structure where structure is required in
data capture/display but where the terminology can't provide a
meaningful subset. Or it may be a specific list of values for a
particular use case where terminology is not really necessary or helpful
for querying, for example whether a menstrual period is
'lighter/same/heavier than normal'. In any case, any one, some, or all
of the internal codes can be bound to any terminology code (or even
multiple terminologies), if desired.
There will not be many situations where a text datatype will be bound to
a terminology subset in an archetype as this commits every user in every
use case to using a terminology subset. Many will not have access to
the terminology, it may not be geographically relevant etc etc - there
will be many situations where this is not ideal, especially the more
'international', or potentially shareable. the archetype is.
So, in practice:
* Most terminology subsets (which represent valuesets) will be bound
within templates to a text datatype that was represented as 'free
text or coded' in the archetype. This gives the required
flexibility for each clinical use case.
* On the other hand, it is likely that there will be many examples
where terminology codes will be 'one to one' bound within the
archetype to root nodes, data elements or internal code values,
where common agreement for that code can be found amongst the experts.
Regards
Heather
Andersson Richard wrote:
