Stream: questionnaire
Topic: Four extensions for units?
Paul Lynch (Dec 12 2018 at 21:24):
I am confused about why we seem to have four extensions that can be used for units for a question. @Xiaocheng Luan just reminded me about:
http://hl7.org/fhir/extension-elementdefinition-allowedunits.html
which we are using in the LHC-Forms Questionnaire import. This extension supports both a CodeableConcept and a reference to a ValueSet. But, we also now have:
http://hl7.org/fhir/2018Sep/extension-questionnaire-unit.html
http://hl7.org/fhir/2018Sep/extension-questionnaire-unitoption.html
http://hl7.org/fhir/2018Sep/extension-questionnaire-unitvalueset.html
Couldn't allowedunits be used to handle the use cases of these other three?
Lloyd McKenzie (Dec 12 2018 at 21:37):
AllowedUnits isn't allowed for Questionnaire. "unit" says what the unit for question of type decimal or integer is. It's used for converstion. option and value set define what the allowed units are for selection if the type is Quanity
Paul Lynch (Jan 10 2019 at 17:36):
Can questionnaire-unit be used to specify a default unit for questions of type Quantity with multiple questionnaire-unitOption choices?
Lloyd McKenzie (Jan 10 2019 at 18:45):
No. It's not a default
Paul Lynch (Jan 11 2019 at 00:54):
"unit" says what the unit for question of type decimal or integer is. It's used for converstion.
Why would something that has a unit not be of type quantity? (Also the item type valueset page (under quantity) associates the questionnaire-unit extension with the quantity type.)
Lloyd McKenzie (Jan 11 2019 at 01:41):
Supporting "quantity" in a Questionnaire is actually quite unusual. Most questions have a type of decimal or integer. The unit is either fixed or the answer to a separate question. Having a question whose answer is a complex combination of value + code + system is a much more sophisticated capability
Last updated: Apr 12 2022 at 19:14 UTC
