Demographic Statistics

(population statistics), the area of statistics concerned with the application of statistical methods to the collection, processing, presentation, and analysis of data describing the size, characteristics, distribution, and movement of the population or various of its subgroups of a given country or territory. The concept of demographic statistics also comprises the sum total of numerical data on population and sometimes also the practical activity involved in the collection and processing of the data.

The theoretical base of Soviet demographic statistics is Marxist-Leninist demography. The methods worked out by demographic statistics are based on the propositions of the theory of statistics. Demographic statistics is one of the important instruments of demographic analysis, and the information that it accumulates serves as a factual basis for many socioeconomic analyses of the population. Demographic statistics works out methods of collecting data on the population and of making current and long-range estimates of population size and composition; and it develops methods of measuring, comparing the intensity, and analyzing the factors in demographic processes (such as birth rates, mortality, marriage, and divorce). Other, nonstatistical demographic methods have historically been associated with demographic statistics—in particular, the construction of mathematical population models (for stationary, stable, and other conditions), the analysis of functions of population reproduction presented in the form of demographic tables (fertility, mortality, marriage), and the elaboration of general characteristics of the reproduction pattern of the population, as well as models that imitate demographic processes.

The analysis of the laws of population development presupposes the measurement of the intensity of demographic processes by means of the calculation of coefficients that express the frequency of the various demographic events (births, deaths, marriages, and divorces) among the population or groups thereof or the calculation of the probabilities of occurrence of these events. Since the intensity of these events is a function of age, indexes for various ages are particularly important. A selection of such indexes computed for the totality of individuals of the same age over various periods of their lives characterizes the reproduction of the actual age group. In practice, age indexes for a conventional or hypothetical age group are employed more frequently: these characterize the intensity of demographic processes for one given period but relate to people of different age groups. Indexes for various age groups—children, people able to work, people of child-bearing age—are of independent importance. The characteristics of the processes of family formation and disintegration are important.

The registration of the population serves as a source of the data of demographic statistics. Traditionally, a distinction is made between the recording of the characteristics of the population at a particular moment of time and the registration of its movement. Information on the characteristics of the population, including its size and distribution and its break-down in terms of social groups, sex, age, education, nationality, occupation, and so on, is obtained in censuses of the population carried out at a given time in a centralized fashion and according to a common program; these censuses provide a kind of snapshot of the population. The natural movement of the population—the changes in its size and composition resulting from births and deaths (as well as marriages and divorces)—is kept track of by a running account of these events, based on the registration of civil acts. Mechanical population movement, or migration, is calculated in censuses or by means of registration of changes in domiciles. In some countries, permanent lists, or so-called registers of the population, are kept. In the USSR, one such form of list is the rural soviet book of registrations in terms of households. Information on population and on demographic processes is also obtained from regular or occasional sample surveys, which are particularly important in countries where population record keeping has not been established. Sample surveys based on the so-called anamnestic method (that is, by means of questions about past events) are used to obtain indexes on the actual age group. The material provided by these sources makes it possible to derive estimates of the size and age-sex composition of the population between censuses, as well as to obtain information essential for the analysis of demographic processes on a territorial basis.

The present population information system began to take shape in the second half of the 19th century; it functions only in economically developed countries. The contemporary stage in the development of demographic statistics is characterized by an expanded arsenal of methods for the collection and analysis of information, the use of approaches borrowed from mathematics and sociology, and the extensive use of computers in processing data. In the USSR, as in most of the countries of the world, the data of demographic statistics are usually gathered and processed by state statistical bodies. The functions of the state statistical service also include long-range population calculations, current estimates of size and age-sex composition of the population, and the construction of demographic tables and elements of demographic analysis. Demographic statistical data are published in special journals, statistical collections, and demographic year-books in many countries of the world.