This Chapter describes methods for defining the level of damage from an event, its impact on the functional status of the affected society, and for identifying the needs that result from the damage. The event may produce damage to the population (injuries, death), its constructions and societal functions, and/or to the environment. Societal functions are described as production functions with inputs, transformations, consumption of resources, and outputs. Distinction between available supplies, requirements, and needs is stressed. The differences between damage assessments and needs assessments are described. Needs for goods and services that are greater than the available level of supplies produces deficits. The concept of thresholds of available resources required to maintain the pre-event functional state, those necessary to sustain basic functional states, and those required for survival is developed. Surplus of available supplies is subdivided into those needed for contingencies and those that comprise luxuries. Indicators are required that define either the level of function or the level of available supplies.Distribution of available supplies (who receives them) impacts whether critical and functional requirements of a population, or part of the affected population, are satisfied.When critical requirements are not met, the crude mortality rate increases. Severity scoring of the damage sustained and the effects of responses is described. All damage and needs assessments and responses to them relate to the pre-event state of the affected society, and the objective of disaster responses is to return the affected society to its pre-event functional state.

The document is published in collaboration with the following organisations: the European Society of Emergency Medicine (Leuven); the European Resuscitation Council (Antwerpen); the Air Medical Physician Association (Salt Lake City, US); the German Interdisciplinary Association of Critical Care Medicine; and the German Society of Anaesthesiology and Intensive Care. The document is to be published jointly in the following journals: 1) Trauma Care (ITACCS); 2) Resuscitation; 3) Prehospital and Disaster Medicine; 4) European Journal of Emergency Medicine; 5) Trauma and Emergency Medicine Journal (SA); 6) Emergency Medicine(Norway); 7) JEUR; and 8) Notfall und Rettungsmedizin (Germany).

For the past two decades, prehospital trauma care has been addressed almost generically in terms of the related approaches to epidemiology, research, and management. However, evolving directions in research have helped emergency medical services (EMS) practitioners to delineate more focused treatment strategies according to the mechanism of injury, anatomic involvement, and the patient's clinical condition. Recent studies in the areas of trauma-associated circulatory arrest, severe blunt head injury, and post-traumatic hemorrhage following penetrating truncal injury suggest that current standard approaches to patient care should be reconsidered. In turn, this need for re-examination of trauma management strategies calls for the development of appropriate evaluation tools within EMS systems. Proper research design is dependent upon several key issues including: 1) the type of study (system study versus examination of a specific intervention); 2), the population under study; 3) physiological and anatomical scoring method; 4) prospective definitions of interventions and meaningful outcome variables (both morbidity and mortality; 5) relative outcome compared to known standards; and 6) prospective determination of statistical requirements.