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Relationship between Domain and Vocabulary

Vocabulary Users
#1

Hi guys,
I’m just wondering what exactly the domain is.
In definition, domain is in which CDM table a clinical entity should be placed into. There are approximately 40 numbers of CDM tables in OMOP, but there is no table as Spec Anatomic site, Currency, Modifier, Meas Value, and so on…so I’m so confused what it is.

At the result of query,
*UCUM
(Domain ‘Unit’ - Voca ‘UCUM’ - Concept_class ‘Unit’)

*VA Class
(Domain ‘Drug’ - Voca ‘VA Class’ - Concept_class ‘VA Class’)

*SNOMED
(Domain ‘Spec Anatomic Site’ - Voca ‘SNOMED’ - Concept_class ‘Body Structure’)
(Domain ‘Metadata’ - Voca ‘SNOMED’ - Concept_class ‘Model Comp’
(Domain ‘Observation’ - Voca ‘SNOMED’ - Concept_class ‘Observable Entity’)
(Domain ‘Observation’ - Voca ‘SNOMED’ - Concept_class ‘Context_dependent’)

SNOMED is so huge Vocabulary system…

I konw Concept_class is Vocabulary’s lower class.
Is domain Vocabulary’s lower class either?

#2

ETL, the domain tells you which table/field the concept should go into. Non-ETL, the domain tells you “what” that concept is. In the native source, just because something is a diagnosis, drug, or procedure, doesn’t mean that from an observational point of view, it is the same. For example, in ICD9/ICD10, “Family history of Asthma” is a diagnosis. In OMOP, it has a domain of “Observation” because this is not something that happened to the actual patient. It is something is observed that there is a family history of asthma.

Domain - Unit . The concept ID for this domain would go into the Unit Concept ID
Domain - Drug. This concept along with its record would create a record in the Drug Exposure table
Domain - Spec Anatomic Site would go into the Specimen table
Domain - Observation would go into the Observation table.

In OMOP, you don’t just look at the vocabulary and think that that vocabulary is one thing or another, like all SNOMED codes are Condition. You must look at the domain to determine what that concept is.

@MichealJeong I see that you are asking a lot of good fundamental questions about OMOP in the forums. We have a video on OMOP Vocabulary/CDM for beginnings available online. You may want to look at that as it may help you with many of your questions. The video from last year is located at https://www.ohdsi.org/past-events/2018-tutorials-omop-common-data-model-and-standardized-vocabularies/

Also, if you get a chance, please join us at the OHDSI Symposiums. We teach the class there as well.

#3

Thank you @mvanzandt
It is really helpful :slight_smile:

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