Examining the validity of pressure ulcer risk assessment scales: developing and using illustrated patient simulations to collect the data.

Simulations are of particular advantage in research studies where large samples are necessary to achieve statistical power and the information must be collected under uniform conditions in order to aid interpretation. In the study reported below, simulation was achieved through the use of medical photography accompanied by case studies of the same patients. All information was collected on the same day. The purpose of the study was to determine the validity of the three pressure ulcer risk assessment scales most commonly used in clinical nursing practice in the UK. Each clinical nurse assessed the same four patients using three risk assessment scales and a visual analogue scale designed to capture their own clinical judgement. External validity was assessed by a panel of tissue viability experts who provided independent ratings. Data were obtained from 236 clinical nurses, yielding 941 risk assessments. Experience with this approach to data collection suggests that it requires careful planning. This should include measures to ensure that the simulated information is valid and that all data collectors have been adequately trained and are able to motivate the nurses participating in the study. Providing consideration is given to these issues, the use of simulation can help to collect data that would be difficult to obtain by more conventional means. It is also important to recognize that clinical decisions are de-contextualized in simulations because they are reduced to verbal and visual summaries. The decision to use simulations should thus be taken only if this is acknowledged.