8.4 Measurement of infant mortality

The level of infant mortality is measured by the infant mortality rate, in which the number of deaths in infancy, i.e. under one year old, is divided by the number of live births during the same year. The derived figure is multiplied by one thousand, that is, the figure is expressed in pro mille.

The infant mortality rate is calculated for the calendar year so that all liveborn in a certain year are included, that is, all those aged 0 in the course of that year. In contrast, those dying at the age of under one may have been born during the preceding year or died at age one in the year following the year of calculation.

To correct this inaccuracy - though minor - the infant death rate can be calculated by birth year cohort. Thus both births and deaths are derived from the same population.

Often when we talk about infant mortality we actually mean child mortality, which is the death rate of those aged 0 to 4. This rate is particularly used for comparing developing countries. The primary reason for this is that in developing countries child mortality is still high after the child's first year.

The infant mortality rate is often used to compare the living standards of countries. The higher the rate, the lower is the living standard in that country. While in 1999 the infant mortality rate was 3.6 in Finland and 7.0 in the USA, in Ethiopia it was 104 and in Afghanistan 147!