FHIR Chat · EnableWhen behavior with operator `exists`

Stream: questionnaire

Topic: EnableWhen behavior with operator `exists`

Jing Tang (Jun 30 2021 at 12:32):

In this example: http://www.hl7.org/FHIR/questionnaire-example-bluebook.json.html, the enableWhen expression for question vitaminKgivenDoses evaluates to true if an answer is given to a boolean question. In reality though, once you have ticked the checkbox, unchecking it would only change it to false, rather than clearing the answer. So the behavior of this questionnaire is a little unexpected to me - the additional question will not go away after you uncheck the checkbox. Solutions? 1) rewrite this example and only show the new question if and only if a true answer is given to the boolean question 2) make the rendering tool clear false answer when a checkbox is unchecked. 2) seems very odd to me and inconsistent with how answers are handled... so should we update this example? Thanks!

Brian Postlethwaite (Jun 30 2021 at 12:37):

vitaminKgiven is a choice type (coded response), so if the selection is cleared, then the group would go away again.

Jing Tang (Jun 30 2021 at 13:44):

sorry yes i think i mixed up two things in my question... about vitaminKgiven: so that is to say the tool should always have a way to clear choice type? that's not so obvious an option for things like radio button group.

Jing Tang (Jun 30 2021 at 13:47):

I was also meant to ask about hepBgiven and its nested question hepBgivenDate. In this case if the parent question is answered but then unticked, should the child question be hidden?

Yunwei Wang (Jun 30 2021 at 13:59):

It depends on how you design the Questionnaire. We had similar issues so we use three values value set yes-no-notSepcified instead of boolean if we really cares the default to be notSpecified. In UI, the item is rendered as a group with three radio buttons.

Lloyd McKenzie (Jun 30 2021 at 14:48):

I think we have a change request in SDC that includes a recommendation that boolean items be rendered with a 3-state control to allow "not answered" to be a choice. However, we can't guarantee all renderers will do that.

Tilo Christ (Jun 30 2021 at 18:28):

This is already the recommended way of doing things today:https://build.fhir.org/questionnaire.html#booleans
In my Faiadashu filler I actually went to great lengths to make sure that everything could be brought back into an untouched state. See http://legentix.com/faidashu/#/ for an implementation of the Bluebook questionnaire that hopefully gets everything right.

Brian Postlethwaite (Jun 30 2021 at 22:02):

My renderer does bools as t/f, options with radios once you choose, that's it, options with a drop down can select the blank entry.

Jing Tang (Jul 01 2021 at 08:33):

thanks all - this makes sense. but i think for nested questions (e.g. the hepBgiven question in the questionnaire i linked) it still is a little strange that answering no would display nested questions.

ps @Tilo Christ awesome demo!

@Kashyap Jois @Fred Hersch

Kashyap Jois (Jul 01 2021 at 09:13):

Yup all this makes sense , thanks @Jing Tang !

Kashyap Jois (Jul 01 2021 at 09:19):

There is still a point that @Jing Tang made which is not clear yet, If a parent item has nested items, should the nested items be hidden until the parent has been answered?

Jing Tang (Jul 01 2021 at 10:19):

i think the question is whether we treat boolean type as a special case and still hide the nested item if the answer to the the parent question is false

Yunwei Wang (Jul 01 2021 at 13:45):

That is a Questionnaire design issue. You can design it either way.

Lloyd McKenzie (Jul 01 2021 at 14:29):

If you have a question with nested questions, the questions nest beneath the answers - so there's nothing to nest within if you don't have an answer to the parent question.

Kashyap Jois (Jul 02 2021 at 05:27):

Lloyd McKenzie said: