The purpose of this monograph is to see whether new data make it possible to re-assess the relative merits of various contending models for the way in which the probability of dying changes with age, at least in the range of ages from 80 to 120.
Thirteen countries have a sufficiently long run of reliable data to be useful for the specialised purposes of the present analysis: Austria, Denmark, England and Wales, Finland, France, Germany (West), Iceland, Italy, Japan, the Netherlands, Norway, Sweden and Switzerland. These countries include almost 40 million persons who reached age 80, and over 120,000 who reached age 100, during the period 1960-1990. The analysis covers over 32 million deaths at age 80 and over in this period.
One of the earliest and still one of the most important examples of mathematical formulae to summarise the way in which the probability of dying depends on age is the “law of mortality” which was discovered by Gompertz (1825). The “law” still gives an excellent approximation, but the situation has now been changed. Following an initial stimulus by Peter Laslett the present authors have assembled a new Archive of Population Data on Aging, which is currently held at the University of Odense, and it contains all the available official statistics on deaths at ages 80 and over in 30 countries since 1960, and in many cases earlier.
The analysis indicates that the probability of dying reaches a value of between about 0.5 and 0.65, for both males and females, at age 120.