Projecting mortality for all countries.
On the basis of an assumption of the persistence of current demographic trends, a model is presented for the projection of short-term (1-2 decades) and long-term (1-2 centuries) mortality rates. Essentially, the model refines calculations of male and female life expectancy and takes infant mortality into account in the selection of the appropriate life tables. The analysis of data from developed and developing countries suggests a short-term life expectancy of 82.5 years and a long-term life expectancy of 90 years for women; male life expectancy is 6.7 years lower. For short-term predictions, the rate of change in the preceding 5 years and the proportion of females enrolled in secondary school are most significant. In terms of infant mortality, the rate is expected to decline to 6/1000 in the short-term and 3/1000 in the long- term. A split life table approach is then used, in which the infant mortality rate determines the level to select for mortality at the younger ages and life expectancy is the basis for level selection at the older ages. Application of this projection approach to 8 countries-- Zaire, Bolivia, Ghana, Pakistan, Thailand, Poland, Costa Rica, and Norway--produced mortality estimates that were within 2 percentage points of existing estimates. Infant mortality projections show a greater deviation, with faster falls than suggested by current World Bank estimates. A rapid mortality decline assumption allows life expectancy to be up to 6% higher in 1985-2100, the crude death rate up to 30% lower, and the infant mortality rate up to 50% lower, resulting overall in a population 8% above that expected under conditions of a medium decline. A slow decline pattern allows life expectancy to be 10% lower, the crude death rate up to 50% higher, and the infant mortality rate up to 170% higher than under conditions of medium mortality declines and produces a 13% population decline.