Primary operation election

All reports that display the mortality, are patient-based, because the mortality is a property of a patient. For reports that show any property of an operation (like surgeon) must elect one operation as the primary operation for given patient. Following text describes how exactly is the primary operation elected. There is a number of patients for which the primary operation is impossible to elect. Those patients do not appear in the reports.

For the given patient:

1. Find the maximum Basic Score from all of the patient's procedures.
   • Known problems: Some procedures do not have Basic Score. Some patients don't have any procedures.
2. Find the procedure with Basic Score equal to the maximum Basic Score. Is is called the primary procedure.
   • Known problems: Some procedures have equal Basic Score, so number of procedures with Basic Score equal to the maximum Basic Score can be greater than 1. This causes the primary procedure be impossible to determine.
3. If the primary procedure was impossible to determine by the maximum Basic Score, find a procedure with Basic Score equal to the maximum Basic Score and priority equal to one.
   • Known problems: As above, but with less cases.
4. If the primary procedure was impossible to determine by the maximum Basic Score and the priority, find the procedure with Basic Score with priority equal to one.
   • Note: This helps to find primary procedures that do not have Basic Score. However, those procedures do not apper in any reports that show the Basic Score. Most of the reports do.
5. If the primary procedure is still impossible to determine, the algorithm gives up here. If the procedure was determined successfully, it continues.
6. Find the operation, during which the primary procedure was performed.
   • Known problems: The primary procedure could be performed during more than one operation.
7. Find the operation, during which the primary procedure was performed and has priority equal to 1.
   • Known problems: The primary procedure could still be performed during more than one operation and have priority equal to 1.
8. If the primary operation could not be determined, the patient is excluded from reports, because it's impossible to tell the date of surgery or any other operation properties.

During the process, only valid operations are taken into account.