Viveremos realmente tanto quanto pensamos? Um estudo sobre medidas de longevidade

Abstract

When mortality is changing, the period life table does not describe the real life experience of the present cohorts in the population. In this sense, the use of current mortality rates to estimate the average lifetime distorts the original concept of life expectancy. Longevity as a cohort measure should be estimated for a real group of people. Given the past declines and likely future falls in mortality, the cohort life expectancy becomes greater than the period life expectancy. Nevertheless, period life expectancy at birth can be viewed as a lagged indicator of the average lifetime of some past cohort (equivalent cohort). This paper explores the time required to find this past cohort (lag) and the differences between life expectancies in a given year (gap) to determine the translation of the period measure in a cohort view. With a shrinking trend of gains in longevity between 1980 and 2050 in Brazil, our results indicate that, for both men and women, the gap is reduced with time, while the lag becomes increasing. That is, over the years, the current estimates of period and cohort tend to be closer, while the equivalent cohorts become more remote.