Life Table Parameters: A Tool for Unlocking Hidden Information

Life table parameters are often used to summarise the pattern of information contained in the life table. However, to be of value, such parameters must offer us new information and. We may distinguish:

1. Parameters which are effectively collinear with e₀, such as Keyfitz H; Gompertz slope coefficient, b. Such parameters may offer us insights into the changing shape of the mortality / survivorship curve as mortality declines, and may be useful proxies for the average level of mortality in the population. However, they can provide little fresh information as to how a specific pattern of mortality is related to the environmental, material, social or historical conditions in which the population lives;
2. Parameters which contain information about the distribution of deaths over the life span which cannot be directly derived from the level of mortality, such as disparity (e^†); Theil's entropy (T); inequality measures (Theil, Gini). These parameters will be correlated, but not collinear, with e₀. The challenge, then, is to see how these parameters can be related, net of e₀, to the social and material conditions in which the population lives.

In this presentation, we shall summarise a number of such parameters, some better known than others, using the HMD set of life tables as well as economic social and political data from the UN, World Bank, Economist Intelligence Unit, etc. We shall consider:

1. which parameters belong to Group 1 and what they can tell us about the changes in the mortality and survivorship curve as mortality declines;
2. which parameters belong to Group 2 and what they can tell us about the variations in the pattern of mortality at any given mean level, and the origin of these variations in the conditions in which the population members live their lives.