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Defining a cohort in Atlas through a ratio between two measurement values

(Andreas Weinberger Rosen) #1

Dear all,

I’m trying to define a cohort through a ratio between two measurement values (neutrophils and lymphocytes) in Atlas, however I have been unable to do so. Has anyone been in a similar situation and found a way to solve this?

Thank you in advance.

(Chris Knoll) #2

No, there currently isn’t a way to derive a value between records in the cohort definition framework.

Would it be possible for you to inject these ratio values into your measurement table at ETL time? Then you simply create a measurement criteria looking for that concept (the ratio of A/B) with the specified value (value as number = ratio between measurements, which you can look for a value greater than or equal to the specified ratio you seek).

The key is knowing when this ‘ratio’ occurred. If you take 2 different measurement records and calculate a ratio, what is the date the ratio occurred? The date when things occur in data is very important to the cohort building framework.