A disease classification is a system of categories to which morbid entities are assigned according to established criteria [World Health Organization (WHO), 1993]. It is used to organize information so as to permit easy storage, retrieval, and analysis of data. The WHO quotes William Farr in 1856 saying “Classification is a method of generalization. Several classifications may, therefore, be used with advantage; and the physician, the pathologist, or the jurist, each from his own point of view, may legitimately classify the diseases and the causes of death in the way that he thinks best adapted to facilitate his inquiries, and to yield general results.” (WHO, 1993, p. 73). An injury classification scheme should allow for the capture of information about the nature of the injury, the body region affected, the external cause, intentionality, and circumstances, such as location, activities, and products involved.

This chapter focuses on how injuries are classified and counted, primarily in health data systems, and how the data can be presented and used in research.

Classifying Injury

Injury in the International Classification of Disease (ICD), and the Clinical Modification of the International Classification of Disease (ICD CM)

The ICD, a product of WHO, is the most widely used classification scheme for coding deaths and morbid conditions. It is designed to promote international comparability in the collection, processing, classification, and presentation of mortality and morbidity statistics. The ICD provides the essential guidelines for the coding and classification of cause-of-death and morbidity data.