Decomposing the Modal Age at Death, Its Number of Deaths, and Standard Deviation.

Paola Vazquez-Castillo, University Of Southern Denmark
Vladimir Canudas-Romo, Australian National University

Background: The modal age at death is a longevity measure that summarizes the most common lifespan. Age- decomposition of longevity measures, such as life expectancy and lifespan deviation, are among the existing demographic tools. However, how different ages contribute to changes in the modal age at death and its related measures remains unknown. Objective: To decompose the modal age at death, the number of deaths at the mode, and the standard deviation around the mode. Methods: Using data from the Human Mortality Database, we present the decompositions of the modal age at death and its related measures from 1985 to 2019. The changes over time of these measures were decomposed using the stepwise algorithm by Andreev, Shkolnikov, and Begun (2002). Results: A common trend in all studied countries is that the changes in the mode are mostly explained by the ages around it. Increases in the number of deaths concentrated at the mode are observed, suggesting mortality compression, with ages younger than the mode explaining this concentration. Furthermore, the standard deviation decreased in most countries, with ages around the mode having an important impact. The latter measure is still affected by the decrease in infant mortality.

Keywords: Decomposition analysis, Mortality and Longevity, Population Ageing, Mathematical demography

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