Reducing the number of medical errors significantly is the challenge for the coming decade. In medicine and in surgery, in particular, errors are traditionally treated as being committed by individuals. To reduce human errors, two approaches can be used: the person approach and the systems approach. In the systems approach, the operator is not blamed, but the system is analyzed in order to find the causes of errors. Furthermore, defenses are built into the system so that errors will not result in an adverse outcome anymore. This article aims to provide insight into the systems approach.