Rectangularization revisited: Variability of age at death within human populations*

Abstract

Rectangularization of human survival curves is associated with decreasing variability in the distribution of ages at death. This variability, as measured by the interquartile range of life table ages at death, has decreased from about 65 years to 15 years since 1751 in Sweden. Most of this decline occurred between the 1870s and the 1950s. Since then, variability in age at death has been nearly constant in Sweden, Japan, and the United States, defying predictions of a continuing rectangularization. The United States is characterized by a relatively high degree of variability, compared with both Sweden and Japan. We suggest that the historical compression of mortality may have had significant psychological and behavioral impacts.

Long-run trends of human aging and longevity

“…Inspired by this fact, some gerontologists have concluded that future life expectancy at birth will unlikely exceed 85 years (Fries 1980;Carnes and Olshansky 2007). The problem with such a hypothesis is that-although the virtually zero background mortality leaves no scope for improvement-we cannot (yet) see any slowdown or convergence of life expectancy in the data (Wilmoth 1997(Wilmoth , 1999. This means that recent advances of life expectancy must have originated from a process that is reflected by a change of the Gompertz parameters.…”

“…1900-1924and 1975-1999. Dashed blue line: Survival function in 1975-1999. Solid orange line: Survival function in 1900-1925 First, a rectangularization or compression of morbidity is clearly visible.…”

“…Two salient phenomena can be observed. 1900-1924and 1975-1999. Dashed blue line: Survival function in 1975-1999.…”

“…Defining human life span as the maximum attainable age at death, as suggested in many general dictionaries and many older contributions in biology, is certainly misleading (Wilmoth 1999;Carey 2003). Conceptually, this idea is refuted by the insight that "however old we are, our probability to die within the next hour is never equal to one" (Jacquard 1982).…”

Life Expectancy, Schooling, and Lifetime Labor Supply: Theory and Evidence Revisited

“…The process of progressive rectangularization of the survival function has been documented also by Wilmoth and Horiuchi (1999) for a sample of countries that have undergone the demographic transition and, more recently, by Strulik and Vollmer (2013), for the period 1900-2000 in a large cross-section of countries. 14 The same pattern has been documented for the preindustrial period 1000-1900 by de la Croix and Licandro (2012) using a cross-country data set on the mortality of famous individuals.…”