#HospitalHospital identifier
#SiteLocation of the hospital
Year Year (most recent year in the SQLape_input.txt file, with at least 10% of records)
#PatientPatient identifier
#CaseIndex stay identifier
DateIndexDate of index operation (each day = another eligible operation)
AgeAge at admission
Gender1 = male, 2 = female
Programmed1=planned, 0=unplanned (corresponding to “admission mode” = 1 or 3 in SQLape_input.txt file)
#Group-RO Clinical groups, used to compute expected rates (labels in Excel table)
AdmissionDateAdmission date of the index stay (each eligible discharge)
DischargeDateDischarge date of the index stay (each eligible discharge)
RO1   Expected rate (see prediction models for more details, benchmark)
RO0Observed rate (1 if potentially avoidable reoperation, 0 if not)
ReoperationDate Date of the reoperation
RODelayReoperation date – previous operation date