The word "longevity" is sometimes used as a synonym for "life expectancy" in demography - especially when it concerns someone or something lasting longer than expected (an ancient tree, for example) - however, the two words have slightly different definitions. In a similar dichotomy to "precision" and "accuracy", "longevity" refers to the average number of years that a single person lives, whereas "life expectancy" refers to the number of years that the average population lives. This is illustrated by the fact that a drastic increase in life expectancy (due to a larger portion of the population beginning to live longer) may be accompanied by a small increase in the overall longevity of the population.

Reflections on longevity have usually gone beyond acknowledging the brevity of human life and have included thinking about methods to extend life. Longevity has been a topic not only for the scientific community but also for writers of travel, science fiction, and utopian novels.

There are many difficulties in authenticating the longest human life span ever by modern verification standards, owing to inaccurate or incomplete birth statistics. Fiction, legend, and folklore have proposed or claimed life spans in the past or future vastly longer than those verified by modern standards, and longevity narratives and unverified longevity claims frequently speak of their existence in the present.

A life annuity is a form of longevity insurance.

Read more about Longevity:  History, Present Life Expectancy, Long-lived Individuals, Longevity and Lifestyle, Longevity Traditions, Future, Non-human Biological Longevity, Biological Immortality

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... The equation reveals that as ME drops below 20%, for W < one gram, MR/MPLS increases so dramatically as to endow W with virtual immortality by 16% ... The smaller W is to begin with, the more dramatic is the increase in MR as ME diminishes ...
List Of Philippine Presidents By Longevity
... This is a list of Philippine Presidents by longevity, as of February 8, 2013 ... Two measures of the longevity are given - this is to allow for the differing number of leap days occurring within the life of each President ...
Chengmai County - Demographics - Longevity
... Of the total 565,000 people living in the county, 18,500 are more than 80 years old, 896 of which are couples. ...
List Of Portuguese Presidents By Longevity
... This is a list of Portuguese Presidents by longevity ... Two measures of the longevity are given ... Where the person in question is still living, the longevity is calculated up to 3 February 2013 ...

Famous quotes containing the word longevity:

    Every thing teaches transition, transference, metamorphosis: therein is human power, in transference, not in creation; & therein is human destiny, not in longevity but in removal. We dive & reappear in new places.
    Ralph Waldo Emerson (1803–1882)