Although pressure ulcer (PrU) development is now generally considered an indicator for quality of care, questions and concerns about situations in which they are unavoidable remain. Considering the importance of this issue and the lack of available research data, in 2010 the National Pressure Ulcer Advisory Panel (NPUAP) hosted a multidisciplinary conference to establish consensus on whether there are individuals in whom pressure ulcer development may be unavoidable and whether a difference exists between end-of-life skin changes and pressure ulcers. Thirty-four stakeholder organizations from various disciplines were identified and invited to send a voting representative. Of those, 24 accepted the invitation. Before the conference, existing literature was identified and shared via a webinar. A NPUAP task force developed standardized consensus questions for items with none or limited evidence and an interactive protocol was used to develop consensus among conference delegates and attendees. Consensus was established to be 80% agreement among conference delegates. Unanimous consensus was achieved for the following statements: most PrUs are avoidable; not all PrUs are avoidable; there are situations that render PrU development unavoidable, including hemodynamic instability that is worsened with physical movement and inability to maintain nutrition and hydration status and the presence of an advanced directive prohibiting artificial nutrition/hydration; pressure redistribution surfaces cannot replace turning and repositioning; and if enough pressure was removed from the external body the skin cannot always survive. Consensus was not obtained on the practicality or standard of turning patients every 2 hours nor on concerns surrounding the use of medical devices vis-à-vis their potential to cause skin damage. Research is needed to examine these issues, refine preventive practices in challenging situations, and identify the limits of prevention.

Risk indicators are metrics that are widely used in risk management to indicate how risky an activity is. Among different types of risk indicators, early warning systems are designed to help decision makers predict and be prepared for catastrophic events. Especially, in complex systems where outcomes are often difficult to predict, early warnings can help decision makers manage possible risks and take a proactive approach. Early prediction of catastrophic events and outcomes are at the heart of risk management, and help decision makers take appropriate actions in order to mitigate possible effects of such events. For example, physicians would like to prevent any adverse events for their patients and like to use all pieces of information that help accurate early diagnosis and interventions. In this research, first we study risk assessment for occupational injuries using accident severity grade as an early warning indicator. We develop a new severity scoring system which considers multiple injury severity factors, and can be used as a part of a novel three-dimensional risk assessment matrix which includes an incident's severity, frequency, and preventability. Then we study the predictability of health outcome based on early risk indicators. A systems model of patient health outcomes and hospital length of stay is presented based on initial health risk and physician assessment of risk. The model elaborates on the interdependent effects of hospital service and a physician's subjective risk assessment on length of stay and mortality. Finally, we extend our research to study the predictive power of early warning systems and prognostic risk indicators in predicting different outcomes in health such as mortality, disease diagnosis, adverse outcomes, care intensity, and survival. This study provides a theoretical framework on why risk indicators can or cannot predict healthcare outcomes, and how better predictors can be designed. Overall, these three essays shed light on complexities of risk assessments, especially in health domain, and in the contexts where individuals continuously observe and react to the risk indicators. Furthermore, our multi-method research approach provides new insights into improving the design and use of the risk measures. / Ph. D.