major public health problem (also see Chapter 2). As the availability, accessibility, and quality of the data have improved, they have played an increasingly important role in the development and evaluation of interventions at national, state, and local levels. However, significant impediments to effective injury surveillance remain, notably the high costs of development and maintenance of surveillance systems. Therefore, priority attention should be given to the improvement or expansion of existing data systems and to the development of efficient strategies for linking data across systems to gather additional and more complex information. Additionally, surveillance systems are dependent upon the quality of coded data. This chapter briefly discusses coding issues, and describes national, state, and local sources of injury data and points to areas where improvement is necessary.
The World Health Organization's (WHO) International Classification of Diseases (ICD) is the most widely used system for coding and classifying the nature and external causes of injury (WHO, 1975). Originally developed in the late 1800s, the ICD is now in its tenth revision. Coding of U.S. mortality data will shift from ICD-9 to ICD-10 starting in 1999. To enhance the use of the ICD for coding nonfatal injury, the National Center for Health Statistics (NCHS) developed a clinical modification (CM) of the ninth revision of the ICD (ICD-9CM) that is the most commonly used classification system for morbidity reporting throughout the United States (U.S. DHHS, 1997). Work is currently under way to develop the clinical modification of ICD-10; its implementation is not expected until the year 2001. Use of the tenth revision of ICD and ICD-10CM will require major adjustments in the way nosologists and researchers approach data collection and analyses. In introducing ICD-10 and its clinical modification, it will be important to ensure that users are adequately trained to take full advantage of its added flexibility and specificity.
The ICD-9 diagnostic codes characterize the nature of injury (e.g., open wounds and lacerations, fractures, sprains and strains, burns) as well as the affected region of the body. These codes are fewer in number than the codes in the ICD-9CM and historically have not been updated between revisions of the ICD. Consideration is being given for an updating process for ICD-10. For mortality, the nature of injury is considered to be a contributing rather than the underlying cause of death, which, by definition, is the external cause of the injury. Thus, to know the nature of the injuries contributing to the death, a researcher must have