Interpreting changes in life expectancy during temporary mortality shocks

Area of Science:

• Demography
• Mortality Science
• Public Health

Background:

• Life expectancy is a key mortality indicator, but its interpretation falters during sudden mortality shocks like pandemics.
• Secular trends in life expectancy can obscure the impact of temporary mortality events.
• Existing interpretations of life expectancy changes are insufficient for understanding mortality shocks.

Purpose of the Study:

• To offer a new perspective on interpreting life expectancy changes during mortality shocks.
• To clarify the meaning of life expectancy declines in the context of temporary, severe mortality events.
• To provide a more accurate metric for assessing the impact of mortality shocks.

Main Methods:

• Analysis of period life table models.
• Comparison of synthetic cohort and stationary population models.
• Reinterpretation of life expectancy differences based on population models.

Main Results:

• Life expectancy differences are typically viewed as cohort longevity variations.
• An alternative interpretation views life expectancy changes as premature mortality in a death cohort.
• This alternative interpretation is more suitable for temporary mortality shocks.

Conclusions:

• The decline in life expectancy during mortality shocks represents age-standardized reduction in lifespan for those dying.
• This metric provides a clearer understanding of mortality shock impacts than traditional interpretations.
• Accurate interpretation is crucial as life expectancy is widely used to report mortality trends.