QuestionnaireResponse tag with no system

[cmoesel]

The standard HL7 FHIR Validator issues the following warning when validating QuestionnaireResponses generated by lforms:

A code with no system has no defined meaning, and it cannot be validated. A system should be provided

This is because lforms adds a tag with a code but no system:

"tag": [ {
  "code": "lformsVersion: 42.2.1"
} ]

Have you considered adding a system so that validators don't produce that warning?

[bethtech]

There is no code system could make the 'code' ("lformsVersion: 42.2.1") computable. We could either use 'display' or provide a customized/fake 'system', or not to set this tag on QuestionnaireResponse at all.

From https://build.fhir.org/datatypes.html#Coding:
"In some cases, the system might not be known - only the code is known. In this case, no useful processing of the code may be performed unless the system is known implicitly through knowledge of the context (e.g., from a known device/source). This practice should be avoided where possible, as information sharing in a wider context is very likely to arise eventually, and codes cannot be used in the absence of a known system. Thus, systems SHOULD populate the Coding.system whenever the system is known."

It looks a code without a system is allowed but not recommended.

My first choice is to not set this tag.

[cmoesel]

I'd be OK with removing it. In some cases it may be useful to know the version of LForms that exported the QR, but those implementations can always add their own tag (or a custom extension) if that's important to them.

That said, this auto-tagging does provide you (the LHC Forms team) a nice way to discover QuestionnaireResponses in the wild that used your software. So I also understand why you might want to keep it.

[plynchnlm]

The purpose of this code is primarily so that our lforms-updater package can know what changes need to be make to fix Questionnaires and QuestionnaireResponses generated by old versions of lforms. These days most changes and fixes we make are backwards-compatible, so lforms-updater is not needed as much. If you don't think you might want to use lforms-updater at some point to update your data to work with a newer lforms (which update might not be necessary, if the changes were made in a backwards-compatible manner) then you can just delete the tag. Since you are running the output through a validator, I think it is less likely you will need lforms-updater.

[cmoesel]

Thanks, @plynchnlm. We made a change on Friday to delete the tag on our side right after we do the export. That works for us -- but it does mean that anyone else using LForms will get that warning if they validate an exported QuestionnaireResponse without first deleting the tag.

That said, I expect it's been like this for a long time, so if I'm the first one to report it, maybe nobody else cares!