This paper discusses which characteristics are appropriate for a measure of period mortality and how are these characteristics met in conventional and tempo-adjusted life expectancy. According to our perspective, a period mortality measure should include exclusively the current mortality and should allow to compare period-specific mortality conditions of two populations or to analyse changes between two periods without depending on past or future mortality trends. By using a simple population model, we show that conventional period life expectancy does not meet these demands since it includes specific assumptions regarding future mortality, which differ between different populations and can ultimately lead to paradoxes which disturb its practical purpose. Tempo-adjusted life expectancy, however, is free of such distortions and thus allows the analysis and comparison of pure period-specific mortality conditions. From these considerations we also derive an interpretable definition for tempo-adjusted life expectancy. We suspect that this lack of definition could be a major reason for the general rejection of mortality tempo-adjustment. Finally, we present estimates for tempo-adjusted life expectancy for the period 2001-2005 for 41 countries showing that tempo effects and their adjustment are not only a technical issue but can have significant impacts on the interpretation of period mortality.
Marc LUY, Senior Scientist, Vienna Institute of Demography Austrian Academy of Sciences, Wohllebengasse 12-14, 6th floor, A-1040 Vienna, Austria.
Christian WEGNER, Research Assistant, Vienna Institute of Demography, Austrian Academy of Sciences, Wohllebengasse 12-14, 6th floor, A-1040 Vienna, Austria.
- DOI: 10.4402/genus-71
Reg. Tribunale di Roma n. 3321/54