Quality assurance programs have been established in industry for decades, with Japan pioneering quality assessment in the 1950s. These principles were later adopted in Western industry, but in medicine, the adoption was delayed due to a lack of competition among healthcare providers. Rising healthcare costs and variations in clinical practice have now spurred interest in quality assurance programs. Tracking hospital performance can reduce surgical morbidity and mortality, and public reporting of outcomes is driving higher standards of care. Reliable outcome data is essential for improving surgical performance and benchmarking. According to Donabedian, medical quality is determined by structure, process, and outcome. In surgery, outcome is the most common indicator of quality. However, there is no precise definition of a "good" or "bad" surgical outcome. In 1992, it was proposed that negative outcomes be divided into complications, failure to cure, and sequelae. Complications are deviations from the normal postoperative course, while sequelae are expected outcomes of the procedure. Failure to cure refers to diseases that remain unchanged or recur after surgery. The incidence of complications is a common surrogate marker for surgical quality, but there is no consensus on how to define and grade them. Various classification systems have been proposed, but none have gained widespread acceptance. A classification system is needed that is simple, accurate, and clinically applicable. The Clavien–Dindo classification, consisting of five grades, is based on the therapy required to treat complications. It focuses on the medical perspective, emphasizing the risk and invasiveness of the therapy used to correct complications. This classification aims to standardize surgical outcome reporting and improve the interpretation of surgical performance.Quality assurance programs have been established in industry for decades, with Japan pioneering quality assessment in the 1950s. These principles were later adopted in Western industry, but in medicine, the adoption was delayed due to a lack of competition among healthcare providers. Rising healthcare costs and variations in clinical practice have now spurred interest in quality assurance programs. Tracking hospital performance can reduce surgical morbidity and mortality, and public reporting of outcomes is driving higher standards of care. Reliable outcome data is essential for improving surgical performance and benchmarking. According to Donabedian, medical quality is determined by structure, process, and outcome. In surgery, outcome is the most common indicator of quality. However, there is no precise definition of a "good" or "bad" surgical outcome. In 1992, it was proposed that negative outcomes be divided into complications, failure to cure, and sequelae. Complications are deviations from the normal postoperative course, while sequelae are expected outcomes of the procedure. Failure to cure refers to diseases that remain unchanged or recur after surgery. The incidence of complications is a common surrogate marker for surgical quality, but there is no consensus on how to define and grade them. Various classification systems have been proposed, but none have gained widespread acceptance. A classification system is needed that is simple, accurate, and clinically applicable. The Clavien–Dindo classification, consisting of five grades, is based on the therapy required to treat complications. It focuses on the medical perspective, emphasizing the risk and invasiveness of the therapy used to correct complications. This classification aims to standardize surgical outcome reporting and improve the interpretation of surgical performance.