Britannica 上 “Life expectancy” 的定义

life expectancy, estimate of the average number of additional years that a person of a given age can expect to live. The most common measure of life expectancy is life expectancy at birth. Life expectancy is a hypothetical measure. It assumes that the age-specific death rates for the year in question will apply throughout the lifetime of individuals born in that year. The estimate, in effect, projects the age-specific mortality (death) rates for a given period over the entire lifetime of the population born (or alive) during that time. The measure differs considerably by sex, age, race, and geographic location. Therefore, life expectancy is commonly given for specific categories, rather than for the population in general. For example, the life expectancy for white females in the United States who were born in 2003 is 80.4 years.

所有跟帖： 

• 计算严格的life expectancy at birth有很长的滞后。所以才用当年死亡率及其年龄分布来推算，但这很容易 -十具- ♂ (19 bytes) () 09/15/2022 postreply 21:23:12