Max Rady College of Medicine

Concept: Double Counting

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Concept Description

Last Updated: 2001-04-17


    When extracting data from the MCHP's databases (medical services/physician claims or hospital discharge abstracts), it is very important to keep in mind double counted records for particular procedures or diagnoses.

    The most common double-counting error occurs when a procedure is recorded as being done on the same person, on the same date or within a 3 day period, at two different hospitals. [Patient likely transferred to another hospital to have the procedure performed].
    Note : This is different from a duplicate record (see Duplicate Records - Hospital Discharge Abstracts concept for more information).
    A SAS macro ( Double Counting ) - (internal access only) has been developed at MCHP to address the issue of double-counting records. The macro is currently dedicated to MCHP hospital discharge abstracts data. The macro assumes that the 12 operation codes, 12 location codes, 12 surgery date codes and hospital codes exist on the data.

    The macro will return a listing of procedures where:

    • The same procedure occurs within a defined number of days.

    • An associated procedure, based on a user defined option, occurs within a defined number of days.

    The macro can look at duplicates between claims, not just the same procedure in the same claim, or it can look at all procedure occurrences simultaneously, including the same claim.

Legitimate "Doublecounts"

    Some procedures can occur more than once within a short interval, or even on the same record. These cases should be counted more than once. When doing research with legitimate double-counts, a decision must be made whether the record will be counted twice or if one of the records will be dropped. The macro output can assist the investigator in making that decision.

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Related terms 


  • Roos LL, Walld R, Wajda A, Bond R, Hartford K. Record linkage strategies, outpatient procedures, and administrative data. Med Care 1996;34(6):570-582. [Abstract] (View)


  • hospital discharge abstracts
  • methods

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Manitoba Centre for Health Policy
Community Health Sciences, Max Rady College of Medicine,
Rady Faculty of Health Sciences,
Room 408-727 McDermot Ave.
University of Manitoba
Winnipeg, MB R3E 3P5 Canada