Tracking progress in mean longevity: The Lagged Cohort Life Expectancy (LCLE) approach

Abstract

Cohort life expectancy is an important but rarely used indicator of mean longevity. In this paper, we show that there are specific advantages in lagging this indicator in time by its own value, an approach termed Lagged Cohort Life Expectancy (LCLE). We discuss the usefulness of LCLE as an indicator for tracking progress in mean longevity and introduce a new interpretation of LCLE as a reference age separating ‘early’ deaths from ‘late’ deaths, or, equivalently, as the age above which individuals in a population can be considered ‘above-average’ survivors. Using data from 15 countries in the Human Mortality Database, we show that current LCLE can be estimated with a relatively high degree of certainty, at least in these low-mortality populations. Results shed new light on levels and trends in mean longevity in these populations.

Keywords:

• mortality
• life expectancy
• period
• cohort
• mortality forecasts
• mathematical demography

Notes

1 Please direct all correspondence to Professor Michel Guillot, Population Studies Center, 3718 Locust Walk, Philadelphia, PA 19104, USA; or by E-mail: [email protected]

2 Acknowledgements: earlier versions of this paper were presented at seminars at the Harvard School of Public Health, Duke University, El Colegio de México, University of Maryland at College Park, the French Institute for Demographic Studies (INED), Université catholique de Louvain, Sapienza University of Rome, French School of Advanced Studies in the Social Sciences (EHESS), University of Tehran, and University of Wisconsin–Madison. The authors thank participants of these seminars, as well as John Bongaarts, Griffith Feeney, Joshua Goldstein, Sam Preston, Sumantra Sen, and reviewers for helpful comments on earlier versions of this paper.