Risk models are used for two main reasons. Firstly, a risk model allows the calculation of the risk of mortality and morbidity of a surgical procedure. This is important as it serves to guide the clinician and the patient about the advisability of an operation by helping to weigh the risk against the benefits. Secondly, a risk model is a method of quality control. Risk-adjusted mortality rate can be used as a measure of the quality of the performance of the hospital, unit, or surgeon. Risk models try to predict the outcome based on preoperative risk factors or variables. There are several such models available; however, The Society of Thoracic Surgeons' (STS) risk score and the EuroSCORE are the widely used models for risk assessment.
Dr. Praveen Varma, “A small step in the right direction.”, Ann Card Anaesth, vol. 16, no. 3, pp. 167-8, 2013.