8.3 Measurement of death rate

Death rate is measured by the general death rate, in which the annual number of deaths is divided by the mean population and multiplied by one thousand. The general death rate can also be calculated from a longer time span. Then an average is calculated from the number of deaths, which is divided by the mean population of the period and multiplied by one thousand.

The same rules apply to the use of the general death rate as to the general birth rate. The general death rate describes mortality in one country in different years fairly well but comparison of countries with different age structures by means of the general death rate may give an erroneous image of the level of mortality.

Age group-specific death rates are calculated by age group for both men and women by comparing deaths at a given age with the mean population of each age group. The age groups used in calculation of age group-specific death rates are usually one-year or five-year age groups.

Death rate is also measured by age group-specific probability of death rates. They differ from age group-specific death rates in that they are not calculated per mean population. The probability of death rates are calculated according to age so that deaths at a certain age are divided by the same age population and, where necessary, the figure is multiplied by one thousand.

For example, the probability of death rate for 72-year-olds is calculated by dividing the number of deaths at age 72 by all persons aged 72 or over. The figure thus obtained expresses the probability to die at age 72. This is called the probability of death rate. The opposite of this is the probability of survival. These rates are used as bases for pension calculations and insurance mathematics and for calculating life expectancy tables.