Counts of all fatalities in the United States are available from vital statistics, although these data are often limited in the information they provide about the exact nature and circumstances of the injury. The National Vital Statistics System is used to describe the epidemiology of injury mortality. While most NCHS data systems are sample based, the National Vital Statistics System is universal in its coverage. For injury-related deaths, the U.S. Standard Certificate of Death has a number of items including the date and time of injury, whether the injury occurred at work, a description of how the injury occurred, the place of the injury, and the actual street location. Clearly, the death certificate is a potentially rich source of statistical information on injuries and could be made more useful by including directives about the acceptable level of detail when describing an injury-related death and by including additional information. For example, questions about the role of drug and alcohol involvement in a death due to injury and, in the case of motor vehicle crashes, specific questions about whether the decedent was a passenger or the driver and the type of vehicle involved. Directives about what information to provide might reduce the current limitation in the vital statistics, particularly with regard to motor vehicle injuries (Robertson, 1998). Specifically, there is a 38 percent underestimation of fatal injuries associated with motorcycle crashes when death certificates rather than police reports are used as the source of data (Lapidus et al., 1994). More detailed information about the nature and cause of death is generally available from a medical examiner's or coroner's investigation and report (see discussion later in chapter).
Uniform data on injuries resulting in hospitalization can be obtained from both the National Hospital Discharge Survey (NHDS) and the Health Care and Utilization Project (Version 3) (HCUP-3). HCUP-3 provides detailed information about the nature of injuries, treatment, and discharge disposition; however, both HCUP-3 and NHDS are limited in that not all states require external cause-of-injury coding on hospital discharge records. In 1994, only about half of the medical records for which an injury was the principal diagnosis had an accompanying E-code. This proportion has increased remarkably to 64 percent in 1996 as the number of states mandating external cause coding has increased. Although procedures exist for estimating distributions by mechanism and intent, given incomplete data, the lack of universal external cause coding of hospital discharges remains a significant impediment to the optimal use of these databases for studying the epidemiology of injury.
National data on nonfatal injuries resulting in a visit to an outpatient setting (e.g., emergency department, clinic, physician office) are available from the National Ambulatory Medical Care Survey (NAMCS), and more recently, the National Hospital Ambulatory Medical Care Survey (NHAMCS). Both the NAMCS and the NHAMCS consist of data abstracted from injury-related visits to hospital emergency departments, hospital outpatient departments, and/or physician offices, whereas the National Health Interview Survey (NHIS) relies on self-reports of injury events. National data on injuries that require medical atten-