- noun the number of years a person, animal, or other organism is likely to live
- The expected value of the number of years a person has yet to live at a given age or, if age is unspecified, at birth, based on the distribution of actual deaths in the population to which the person belongs. Life expectancy in a country is an important indicator of its level of development and well-being.
- noun the number of years a person of a particular age is likely to live
- (written as Life Expectancy)
The statistically expected remaining years of life for a representative person (usually in a specific jurisdiction and by sub-group - male, female, by ethnicity, etc.) at a given age (say, at birth, or having already reached 65). The World Health Organization publishes 'healthy life expectancy' data, which include an adjustment for time spent in poor health. Healthy life expectancy at birth measures the equivalent number of years in full health that a newborn child can expect to live based on the current mortality rates and prevalence distribution of health states in the population.
Unadjusted life expectancy data show enormous variations across the world. A child born in Japan in 2002 had an expectation of life of 81.9 years (85.3 if female) whereas one born in Sierra Leone had an expectation of life of 34.0 years (35.7 if female). In general, females have a longer expectancy than males. Much of the disparity is attributable to high infant mortality rates. In Africa around 40 per cent of deaths occur amongst infants under five years of age. Poor sanitation and associated disease characteristics of grinding poverty - malnutrition, diarrhoea, malaria and infections of the lower respiratory tract - are principal causes. While the past decades have seen a general rise in expectation of life in all countries, in some regions, especially in Africa (for example Botswana, Lesotho, Swaziland and Zimbabwe) life expectation is actually falling on account of HIV/AIDS.