The size and reproduction of the population are some of the main indicators of the level of public life. These concepts reflect the degree of renewal of a generation of people. Reproduction of the population is usually considered as a combination of three types of population movement: spatial, natural and social.
Considering such a process as the renewal of generations, it should be noted its great importance in the development of society. According to many authors, the reproduction of the population is a separate area in social reality. Being a relatively independent process, the renewal of generations is seriously affected by other aspects of social life. At the same time, reproduction of the population has a noticeable effect on other aspects of life. As a result of this interaction, objective requirements are formed for all processes associated with the life of society.
Reproduction of the population is considered a probabilistic phenomenon. It is formed by a mass of single and random incidents - deaths and births. The continued existence of the population provides for the preservation of the basic conditions under which interaction with the external environment is carried out. This is possible, according to experts, with a certain order, and not the randomness of the demographic flow. This, in turn, is the result of management processes taking place in the demographic system. They (processes) are also characteristic of natural conditions. Thanks to them, continuity of renewal of populations of animals and plants, as well as relative stability of numbers are achieved.
After the emergence of human society in managerial processes in the reproduction of populations, qualitative changes have occurred. From this moment, the biological mechanisms of regulation of reproduction were replaced by social ones. The formation of a stable social attitude to the preservation and production of human life provoked the emergence of reproduction of the population as a socially determined process. Of course, this does not mean that specific demographic and biological objective restrictions have disappeared, in accordance with which the system of social regulation of the renewal of populations operates.
A quantitative measure of population reproduction combines the indicator of the birth rate reflected in the corresponding function f (x) and mortality reflected in the survival function l (x). X in these functions is age. A generalized expression of these functions is the gross reproduction rate (R), as well as the average life span e0. In this case, a certain simplification is allowed, which is due to the fact that the indices f (x) and l (x) uniquely determine R and e0, while there is no inverse unambiguous correspondence.
In the population reproduction mode, f (x) and l (x) are exogenous parameters. These indicators uniquely form endogenous parameters: C (x) (population age structure) and the measure of increase in numbers is the net coefficient R0 and the true coefficient of natural growth r. These two indicators characterize the same changes in relation to different time units. In the first case, the generation length T is used, and in the second - the usual calendar temporary measures (usually a year). Thus, the relation r = lnR0 / T is formed.
It should be pointed out that pronounced ethnic and regional differences in the reproduction of the population are noted in Russia.
The reproduction of the Russian population by the second half of the 19th century was characterized by a high birth rate and mortality. In the prewar period, the birth rate began to decline rapidly in industrialized areas.