Possible causes of this departure from international norms were highlighted in a 2013 Institute of Medicine report and have been ascribed to many factors, only some of which are attributed to medical care financing or delivery. These include differences in cultural norms that affect healthy behaviors (gun ownership, unprotected sex, drug use, seat belts), obesity, and risk of trauma. Others are directly or indirectly attributable to differences in care, such as delays in treatment due to lack of insurance and fragmentation of care between different physicians and hospitals. Some have also suggested that unfavorable US performance is explained by higher risk of iatrogenic disease, drug toxicity, hospital-acquired infection, and a cultural preference to “do more,” with a bias toward new technology, for which risks are understated and benefits are unknown. However, the breadth and consistency of the US underperformance across disease categories suggests that the United States pays a penalty for its extreme fragmentation, financial incentives that favor procedures over comprehensive longitudinal care, and absence of organizational strategy at the individual system level.