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What is observation_event_id and obs_event_field_concept_id?

Hello Everyone,

We have survey data stored in Excel. So, I am currently transforming my question and response pairs as records in observation table.

Can you please help me understand the above two fields (obs_event_id and obs_event_concept_id) from observation table with a simple example?

In addition, I would also like to know whether

  1. Qualifier value - What does this field mean? What value goes into this? Can you please help?

  2. Observation_source_value - I am planning to store our column names (our data is stored in excel so, I make use of the column names to kind of help us further in retrieving the data )


1 Like

@DTorok @MPhilofsky - Can you please help me with this?

Not sure where you are getting the column name obs_event_id and Obs_event_concept_id. But for an explanation of the various columns see https://github.com/OHDSI/CommonDataModel/wiki/OBSERVATION

@DTorok - Apologies for not giving the accurate field name in my post. But can I check with you on few things listed below?

  1. Am I right to understand that “observation_event_id” will be same as “visit_occurrence_id” ? I mean patients were questioned when they visited the hospital. So observation_event_id and visit_occurrence_id will be the same. Am I right?

  2. As we have survey data stored in “observation” table, I believe we should be using “survey_conduct” table. In that case, Survey_conduct_id will usually be visit_occurrence_id or procedure_occurrence_id. Am I right?

  3. Can you please help me understand observation_event_field_concept_id with an example? I did refer the link that you sent me, but couldn’t get an idea of what it is



I have not used the observation_event_field_concept_id field or any of the new columns from v6. I think this addition was proposed by @mgurley and the Oncology WG. @Christian_Reich & @clairblacketer will also know more about this.

Qualifier value - This is not a required field. Example: a person has an allergy recorded in the observation_concept_id = 4048476, allergy to cat dander. qualifier_concept_id = 4087703, severe. Most data don’t have qualifiers.

Observation_source_value - You can put whatever you want in this field. Anything and everything. Whatever helps the persons using the data. Excel sheet name and column name are good. Others put the code and text string as it appears in the source.

Sorry, this is not part of the Oncology WG Oncology CDM Extension. None of our structural changes have made it into an official OMOP CDM release yet. I believe these fields were added as part of the support for Survey data. See here:

@ColinOrr2006 might be able to elucidate if I am correct.

@mgurley is correct here. Initially those columns were added to support the storing of survey responses in the OBSERVATION table. The idea was that the survey itself would be captured in the SURVEY_CONDUCT table and the responses would be captured in the OBSERVATION table. The fields OBS_EVENT_ID and OBS_EVENT_CONCEPT_ID were added in order to link the two records between the two tables. Using the example of a survey, the response in OBSERVATION would have OBS_EVENT_ID = SURVEY_CONDUCT_ID and OBS_EVENT_CONCEPT_ID = 1147833 which is the concept id that codes for SURVEY_CONDUCT.SURVEY_CONDUCT_ID. This then associates the two records in the two different tables using concept ids.

Hello @clairblacketer,

Can you please confirm my understanding below?

  1. Survey data is stored in the observation table. Am I right?

  2. Questions are stored as concepts under “observation_concept_id” field and answers are stored under “value_as_concept_id/string/number” fields. Am I right?

  3. Then why do we need Survey_conduct table? What is the use of Survey_conduct table? Is it just store the meta data of survey like when was the survey conducted, what is the survey id (few questionnaires have a standard Id’s) etc? .

  4. If point 3 is right, then “observation.event_id” = “survey_conduct.surbey_conduct_id”. In this case, the ids are nothing but the Survey_ID? For example, EQ5E etc.

Can you please help?