Health, Functioning, and Well-being: Individual and Societal.

As a society we invest an enormous amount of resources in health because we are convinced that health is linked in some way to a person's well-being, and that population health is linked to overall societal welfare. But the nature of this link, and the evidence for it, are more controversial. After exploring current attempts to operationalize well-being in a manner amenable to measurement, in this article we offer a way for securing the link between the provision of health care and individual well-being, and societal welfare by highlighting what matters to people about their health. We argue that it is the lived experience of health and its effect on daily life that matters. This experience is captured by the notion of functioning in the World Health Organization's International Classification of Functioning, Disability and Health. Moreover, viewed as an indicator of health on par with mortality and morbidity, functioning provides the essential bridge that links the provision of health care both to individual well-being and, at the population level, societal welfare.