Quicker detection risk-adjusted cumulative sum charting procedures.

When a patient is operated on, the surgical outcome depends on two major factors: (i) the patient's health condition and (ii) the surgical process comprising the surgeon, the supporting staff, operating environment, and equipment. An outcome is usually represented by one if a patient dies within 30 days of an operation and zero otherwise. Another method of measuring the outcome is to use survival time with truncation on the 30th day for monitoring purposes.