This multicentre research project will also introduce a system of patient safety checklists at each point of care during the surgical patients' stay, not only in the operating theatres (OTs). The system combines new checklists on patient care (parts of SURPASS) with the already established Safe Surgery checklist (WHO) in the OTs. At the same time securing reliability, validity and quality of the patient, morbidity and mortality data will be an essential part of the study.