Questions and Answers

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Q&A - Keyword Starts vs Start

Question

In the Production version of Bonnie, this patient is a Denominator Exclusion, while in Bonnie Alpha, this patient is in the Denominator. To get this patient into the Denominator Exclusion, the first listed Diagnosis in the patient history needs to have an abatement date, which is not required in Bonnie Production. Should these versions of Bonnie provide consistent results?

Answer

What's happening is that the "such that" clause says "start" instead of "starts":

  define "Ex1":
    ["Diagnosis": "Alcohol and Drug Dependence"] FAD
      with ("FirstAlcoholDrugDependenceDx") FADD
        such that FAD.prevalencePeriod start 60 days or less before start of FADD.prevalencePeriod

Because it's not one of the expected keywords, the parser is interpreting that as a query alias, which is basically a no-op, so it's really saying:

  define "Ex1":
    ["Diagnosis": "Alcohol and Drug Dependence"] FAD
      with ("FirstAlcoholDrugDependenceDx") FADD
        such that FAD.prevalencePeriod 60 days or less before start of FADD.prevalencePeriod

And when you use an interval in a "before" like that, it chooses the end of the interval to do the comparison. So, the immediate fix is to just correct the keyword to "starts" instead of "start".