Fact_relationship.relationship_concept_id (table fact_relationship revisited in 2026)

1

If you are using fact_relationship table today, could you post what you are using it for? I am curious and maybe the whole community would like to compare notes / lessons learned ?
I also would like to run a formal informatics study on OHDSI fact linking and do a formal survey of sites/experts willing to have a qualitative interview about use of fact_relationship. (message me or email me or reply here)

Winning use cases can be turned into guidance in official spec or official conventions. Formal functions in OHDSI tools (e.g., Atlas) can be pursued if indeed standardized (e.g., mother-child linkage).

Also, if you will be at the symposium, and see me, stop me and let’s talk various uses of it as of 2026.

There is a 2023 very good discussion at link below
Fact relationships: Searching for an extensible approach - #42 by cce

Now that oncology domain and episode tables have been around longer, the discussion may be slightly different.

Official guidance is:
https://ohdsi.github.io/CommonDataModel/cdm55.html#fact_relationship

2

Hello @Vojtech_Huser,

@Eugene_Paulenkovich and I are presenting “Data Link Odyssey: Methods for Linking Related Records in OMOP CDM v5.4” as a poster presentation at the upcoming OHDSI Global Symposium. As the name implies, our poster discusses the different methods for linking records in the OMOP CDM along with the pros and cons of each method.

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3

Is this the convention for using FACT_RELATIONSHIP to create mother-child and father-child relationships?

Person Table
Person person_id gender_concept_id gender_source_value
Child 101
Mother 202 8532 female
Father 303 8507 male
Fact Relationship Table
domain concept_id_1 fact_id_1 domain_concept_id_2 fact_id_2 relationship_concept_id Relationship
56 (Person) 101 56 (Person) 202 581437 (Child to Parent Measurement)
56 (Person) 101 56 (Person) 303 581437 (Child to Parent Measurement)
56 (Person) 202 56 (Person) 101 581436 (Parent to Child Measurement)
56 (Person) 303 56 (Person) 101 581436 (Parent to Child Measurement]
4

At Fred Hutch Cancer Center we are currently using the fact_relationship table to map hierarchy in care sites, using relationship_concept_id of 46233689 (“Care Site contains Care Site”) and 46233688 (“Care Site is part of Care Site”). As we continue our CDM mapping, I expect we may use the table for other mapping.

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Hello @Cynthia_Sung,

Your example for parent-child linkage is correct.

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We also use fact_relationship to capture family relationships, however instead of using ‘Child to Parent Measurement’ we use any descendant of 4216170 - Immediate family member to allow other relationships as well, e.g. ‘Child’, ‘Mother’, ‘Father’. Relationship direction is not explicit, so we interpret these as ‘Child (of)’, ‘Mother (of)’, etc.