Interpreting Changes in Life Expectancy During Temporary Mortality Shocks

Life expectancy is the most popular mortality indicator with demographers. Unless specified otherwise, it implicitly refers to the value at birth (age 0) of one of the functions derived through a period life table, a key tool of demographic and actuarial analysis. Demographers tend to favor life expectancy because it is a pure measure of the mortality conditions faced by a population, unaffected by that population’s age structure. Life expectancy also has an intuitive interpretation, conditional on the assumption that mortality conditions remain unchanged, as the expected age at death of an average newborn. If life table construction might be limited to an inner circle of demographers and actuaries, this interpretative ease gives life expectancy a much broader appeal.