Compare methods

	Lifespan Inequality	Life Table
Field	Demography	Demography
Family	Process / pipeline	Survival analysis
Year of origin	2003	1984
Originator	Lifespan-variation literature; life disparity formalized by Vaupel & Canudas-Romo	Demographic/actuarial tradition; Chiang
Type	Measures of variability in the age-at-death distribution	Age-structured mortality estimator
Seminal source	Vaupel, J. W., & Canudas-Romo, V. (2003). Decomposing change in life expectancy: A bouquet of formulas in honor of Nathan Keyfitz's 90th birthday. Demography, 40(2), 201–216.	Chiang, C. L. (1984). The Life Table and Its Applications. Robert E. Krieger Publishing. ISBN: 978-0-89874-565-2
Aliases	Lifespan Variation, Life Disparity, Variation in Age at Death	Mortality Table, Actuarial Table, Survival Table, Yaşam Tablosu
Related	4	3
Summary	Lifespan inequality measures how unequally length of life is distributed within a population — the spread of the life-table ages at death, not just their average. Two populations can share the same life expectancy yet differ sharply in how predictable death is: in one nearly everyone reaches old age, in the other deaths are scattered across all ages. A family of measures — life disparity (e†), the standard deviation of age at death, the life-table Gini coefficient, and Keyfitz entropy — quantifies this dispersion, complementing life expectancy with a measure of how fairly survival is shared.	A life table is a systematic, age-structured summary of the mortality experience of a population. It traces a hypothetical cohort of births — conventionally 100,000 — through successive age intervals, recording how many survive, how many die, and how many person-years are lived at each interval. The method was formalized in its modern probabilistic form by Chiang (1984), synthesizing centuries of actuarial and demographic practice into a rigorous statistical framework applicable to human and biological populations alike.