Most pressure ulcers (PU)can be prevented and assessment of the patient skin and risk factors for pressure ulcers is the first step. Epidemiological studies are also an important element in the prevention of PU and requires consistent registration based on standardized definitions and tools. Staff knowledge is critical in this work. However showed a Norwegian pilot study on the prevalence of PU deficient knowledge among nursing staff in terms reliable classification of PU and PU-assessment of risk. The pilot study showed the need for training to reduce the incidence of pressure ulcers and to ensure data quality in future studies.