VALUE_AS_DATETIME in Observation ETL documentation

[yampeku]

Observation ETL conventions mention a non-existing VALUE_AS_DATETIME field

[MelaniePhilofsky]

@yampeku

Thank you for notifying us of the error in documentation located here.

Tagging @clairblacketer or @MaximMoinat to update the documentation

[MaximMoinat]

Made a PR to address this. Note that actually this whole ETL conventions section should move to Themis.

Interesting, the value_as_datetime has come up in the last CDM WG meeting. So I am now curious whether we used to have this field and why it got deprecated.

[MaximMoinat]

For reference, there are four separate Themis conventions in here (and none of them are on Themis currently).

• Records whose Source Values map to any domain besides Condition, Procedure, Drug, Specimen, Measurement or Device should be stored in the Observation table.
• Observations can be stored as attribute value pairs, with the attribute as the Observation Concept and the value representing the clinical fact. This fact can be a Concept (stored in VALUE_AS_CONCEPT), a numerical value (VALUE_AS_NUMBER) or a verbatim string (VALUE_AS_STRING).
• Even though Observations do not have an explicit result, the clinical fact can be stated separately from the type of Observation in the VALUE_AS_* fields.
• It is recommended for Observations that are suggestive statements of positive assertion should have a value of ‘Yes’ (concept_id=4188539), recorded, even though the null value is the equivalent.

[MelaniePhilofsky]

@MaximMoinat

I agree, let's move these conventions over to the Themis convention library.

value_as_datetime was added to the CDM in v6.0. I'm not exactly sure why it didn't move over to CDM v5.4. I don't know of a use case which requires datetime, but I do know of use cases which require value_as_date (without the time portion).