In 1948, the World Health Assembly defined health as “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.”  This definition is still widely referenced, but is often supplemented by other World Health Organization (WHO) reports such as the Ottawa Charter for Health Promotion which in 1986 stated that health is “a resource for everyday life, not the objective of living. Health is a positive concept emphasizing social and personal resources, as well as physical capacities.”

Classification systems describe health. The WHO’s Family of International Classifications (WHO-FIC) is composed of the International Classification of Functioning, Disability, and Health (ICF) and the International Classification of Diseases (ICD).