Information Matrix

Mortality at post-retirement ages has three apparent stages:

1. A broadly Gompertzian pattern up to age 90 (say), i.e. the mortality hazard is essentially linear on a logarithmic scale.

2. The rate of increase in mortality slows down, the so-called "late-life mortality deceleration".

A population consists of individuals, each with their own genetics, lifestyle, and yes, their very own force of mortality. National mortality data, such as held by the Office for National Statistics (ONS), are observed only at the population level and the variation in the force of mortality across individuals of the same age is forever hidden. The purpose of this blog is to show how we can attempt to model this hidden heterogeneity.

In a previous blogs I have looked at seasonal fluctuations in mortality, usually with lower mortality in summer and higher mortality in winter.  The subject of excess winter deaths is back in the news, as the UK experienced heavy mortality in the winter of 2014/15, as demonstrated in Figure 1.