This was a prospective study of children with blunt torso trauma with a goal of identifying high-risk and low-risk indicators of intra-abdominal injury (IAI). The long term objective of the study is to derive, validate, disseminate and implement decision support tools to optimize the evaluation of children with blunt torso trauma, which will lead to reduced morbidity and mortality. The overall objective of this particular study is to develop a clinical decision rule for appropriate use of abdominal computerized tomography (CT) scanning in children with blunt torso trauma. We will create a decision rule that identifies those children in need of emergent CT scan and treatment, while reducing the use of abdominal CT scans in those children with minimal risk of IAI. The study was funded by the Centers for Disease Control and Prevention. Patient enrollment began in May, 2007 and concluded in January 2010. The main paper, Identifying Children at Very Low Risk of Clinically Important Blunt Abdominal Injuries, was published in Annals of Emergency Medicine, in Feb 2013. The public use data set can be requested here.