Rationalizing health care in a changing world: the need to know

The World Development Report 1993 announced that global life expectancy was then 65. Experience in the developed world suggests that the World Health Organization's dictum, 'health is a state of complete physical, mental and social well-being', is simply not attainable for the foreseeable future. As physical health has improved, mental problems have become more prominent and a sense of well-being has declined. Furthermore, as the population ages and medical technology improves, the cost of health care grows almost exponentially. Since the population of the developed world is continuing to age and aging is spreading rapidly throughout the developing world, knowledge is the principal way of dealing with this seemingly intractable problem: we must know, quantitatively, the age-specific causes of ill health, and we must know which means of prevention and treatment are effective. Finally, we must apply that knowledge rationally.