Background Injury and trauma remain important causes of morbidity and mortality globally. Trauma systems have been established to facilitate optimal management of injured patients, including timely access to specialist trauma centres in those who are severely injured. Trauma quality improvement programs have emerged over the past decade to evaluate and improve quality of care delivered by trauma systems and trauma centres. Despite this, there remains little evidence to demonstrate that these quality improvement programs actually improve patient outcomes or whether they are cost-effective. In 2006, a trauma quality improvement program was initiated at Royal Prince Alfred Hospital, Australia. This consisted primarily of the implementation of trauma team activation and resuscitation protocols, and the evaluation of care through the use of clinical indicators (key performance indicators) and measurement of post discharge health status. Objectives This thesis describes a quality improvement program at Royal Prince Alfred Hospital that involved monitoring of all major clinical services involved in the acute care of trauma at this hospital, and evaluates this program with respect to in-patient mortality for severe injury, cost effectiveness and long term outcomes. Methods The studies were conducted at Royal Prince Alfred Hospital (RPA) in New South Wales Australia. The thesis is presented in four main sections. The first section (chapters 1 to 4) provides an outline of the thesis and summarises the current literature on trauma quality improvement programs. Preliminary papers describe the historical context of the trauma service at this institution and discuss the conceptual framework for trauma patient data collection. The second section (chapters 5 to 9) provides background information regarding contemporaneous trends in injury presentations to Emergency Departments and major trauma activity and mortality across NSW. The third section (chapters 10 to 13) details and evaluates the impact of the trauma quality improvement program on long-term major trauma mortality trends at this hospital using time series analysis and its cost effectiveness in a subset of road trauma patients. It also investigates health status outcomes in trauma patients at three and six months after hospital discharge - a project initiated as part of the quality improvement program. Results Injury is one of the leading causes of presentations to Emergency Departments across NSW and the critically injured make up around 1% of total injury presentations. Major trauma in-hospital mortality across NSW has remained stable at around 16% between 2003 and 2014. The trauma quality improvement program at RPA was associated with a significant reduction in major trauma mortality from 16% to 10% after 2007. The incremental cost effectiveness was estimated to be $7600 per year of life saved in the subset of road trauma patients. Analyses of health outcomes after discharge revealed increasing injury severity and upper limb injuries were the only predictors of reduced employment status after injury, and lower limb injuries were associated with reduced physical health status compared to those without lower limb injuries at both 3 and 6 months post discharge. Around 37% of patients reported signs of psychological distress and this did not change significantly during the study interval. Conclusions This thesis has published important new information regarding the clinical and cost-effectiveness of trauma quality improvement programs. It contains the first published studies evaluating these interventions using formal time series and health economics analysis and one of few reporting the intervention in the context of existing injury and trauma management systems in New South Wales Australia