The U.S. Army invests significant resources in recruiting, training, and preparing new soldiers. When a soldier does not complete a full contract term, the Army views this as a net loss. The goal of the research summarized in this report is to determine whether organizational factors matter for producing attrition and to generate hypotheses regarding the mechanisms by which organizational factors generate attrition. The authors made use of the random assignment of soldiers to their first battalion to determine whether the "luck of the draw"-the battalion to which the soldier is assigned and the senior noncommissioned officer (NCO) at that battalion-is directly linked to the observed variation across assignments in eventual first-term outcomes. The authors complemented that analysis with interviews exploring the factors that could be driving differences across units, such as leadership and command culture, availability of soldier supports, management of deployment and training cycles, and installation amenities. The quantitative part of the report shows that organizational factors affect attrition above and beyond the effects of soldier characteristics. The qualitative part highlights potential pathways through which battalion-level characteristics might manifest in differential attrition outcomes. Rather than conceptualizing attrition as a soldier being "fired" for poor performance, this report describes attrition as a process in which leadership may fail to provide needed interventions or to perpetuate a culture in which soldiers want to and are able to remain in service. The authors identify opportunities to address the factors under the Army's control that are associated with attrition. Book jacket.