7.5 Population subject to population change events

Population changes are described by means of key ratios. These key ratios are calculated by proportioning the population change event to the number of population. This population is often a total population, but we can gain a more accurate picture of the frequency of population phenomena if the population selected is the part of the population that is in fact subject to the population change event. For example, we can obtain a better view of the birth rate by focusing on the population of women aged 15 to 49: the population group who are capable of giving birth.

The population subject to population change events is often calculated with regard to age and gender.

In demography the population subject to population changes is often called the risk population. This is not intended in any way as a negative description, after all we may be referring here to something as positive as births.