Panel A shows a frequency histogram and probability density function distribution for the diameter of abdominal aortic aneurysms among the first 700,000 men screened in England. This screening occurred between April 2009 and August 2014. A total of 48 men per 100,000 men screened had aneurysms at or above the mean diameter for aneurysm repair in England, as compared with 76 men per 100,000 screened who had aneurysms at or above the mean diameter for aneurysm repair in the United States. Panel B shows the standardized numbers of repairs of abdominal aortic aneurysms in the United States as compared with the expected numbers of repairs of abdominal aortic aneurysms in England. The results are shown after application of the U.S. probability density for repair at various aortic diameters to the prevalence data for abdominal aortic aneurysms in England at each diameter in the U.K. national screening program. Data on patients in England are from the National Health Service Abdominal Aortic Aneurysm Screening Programme, and data on patients in the United States are from the NSQIP.