Multilingual Demographic Dictionary, second unified edition, English volume

Stable age distribution (STABLE age distribution)

Translation
Section	English 703	Arabic 703	Czech 703	German 703	Spanish 703	French 703	Italian 703	Japanese 703	Portuguese 703	Russian 703	Chinese 703
703-1	intrinsic rate of natural increase	معدل الصميم للزيادة الطبيعية	vnitřní míra přirozeného přírůstku	stabile Wachstumsrate —intrinsische Wachstumsrate	tasa intrínseca de crecimiento natural	taux intrinsèque d’accroissement naturel	tasso intrinseco di incremento naturale —incremento naturale	安定人口増加率（または真性自然増加率）	taxa intrínseca de crescimento natural	Истинный коэффициент естественного прироста	内在自然增长率
703-2	stable population	مجتمع المستقر	stabilní populace	stabile Bevölkerung	población estable	population stable	popolazione stabile	安定人口	população estável	Стабильное население	稳定人口
703-3	stable age distribution	توزع عمري مستقر	stabilní věková struktura	stabile(r) Altersaufbau	composición por edades de la población estable —composición estable por edades	répartition par âges stable	distribuzione per età stabile	安定的年齢分布	distribuição por idade estável	Стабильная возрастная структура	稳定年龄分布
703-4	initial age distribution	توزع العمري الإبتدائي	výchozí věková struktura	ursprüngliche(r) Altersaufbau	composición inicial por edades	répartition par âges initiale	distribuzione per età iniziale	初期の年齢分布	distribuição inicial por idade	Исходная возрастная структура	最初年龄分布
703-5	growth potential	كمون النمو	potenciální růst	Wachstumspotential	potencial de crecimiento	potentiel d’accroissement	potenziale d’incremento	潜在成長力	potencial de crescimento	Потенциал роста	增长潜力
703-6	stationary population	مجتمع المتوقف	stacionární populace	stationäre Bevölkerung	población estacionaria —tabla de mortalidad	population stationnaire —population de la table de mortalité	popolazione stazionaria —popolazione della tavola di mortalità	定常（静止）人口	população estacionária	Стационарное население	作静止人口
703-7	quasi-stable population	مجتمع شبه المستقر	kvazistabilní populace	quasi-stabile Bevölkerung	población cuasi estable	population quasi stable	popolazione quasi stabile	準安定人口	população quase-estável	Квази-стабильное население	准稳定人口
703-8		مجتمع نصف المستقر		pseudo-stabile Bevölkerung	poblaciones semi-estables	population semi-stable	popolazioni quasi stabili
703-9	logistic population	مجتمع الإمدادي	logistická populace	logistische(s) Bevölkerung	población logística	population logistique	popolazione logistica	ロジスティック型人口	população logística	Логистический рост населения	罗吉斯蒂人口
703-10	logistic law	قانون الإمدادي	logistická funkce	Gesetz des logistischen Wachstums	función logística —ley logística	loi logistique	legge logistica	ロジスティック法則	função logística	Логистический закон	罗吉斯蒂法则

It can be shown that when a closed population (701-4) is subjected to constant age-specific fertility and mortality rates (631-8; 412-1) for a sufficiently long period of time, its annual rate of increase will tend to become constant. This constant rate of increase is called the intrinsic rate of natural increase ¹, and a population which has reached this stage is called a stable population ². The proportion of persons in different age groups in such a population will be constant, i.e., the population will have a stable age distribution ³. This stable age distribution is independent of the initial age distribution ⁴ and depends only on the fertility and mortality rates that are kept constant. Human populations never reach exact stability in practice, as fertility and mortality rates constantly change, but the computation of a stable population as a model and of its intrinsic rates may provide an index of the growth potential ⁵ of a set of age-specific fertility rates applied to a non stabilized age structure. Related to the growth potential, the moment of inertia of a population or demographic momentum ^11★ should be mentioned: it refers to the dynamics hidden in the age structure due to a delayed growth response caused by the biological fact that from the time of birth of a cohort (116-2) to the beginning of their period of fertility (620-1) a certain amount of time passes. A population may for this reason still grow, even though the birth rate drops long ago. The reverse case is also possible. The momentum is particularly altered in case of discontinuity in the evolution of births and abrupt reversals of trends. A stable population in which the intrinsic rate of natural increase is zero is called a stationary population ⁶. In such a population the numbers in a given age group are equal to the integral of the survivorship function (431-3) of the life table taken between the upper and lower age limits of the group, multiplied by a factor of proportionality common to all age groups. A quasi-stable population ⁷ is a formerly stable population with constant fertility and gradually changing mortality; characteristics of this type of population are similar to those of a semi-stable population ^8★ which is a closed population with a constant age structure. A logistic population ⁹ is a population growing in accordance with the logistic law ¹⁰ of growth, i.e., a population in which the growth rate decreases as a linear function of the population already alive and which will tend asymptotically to an upper limit.

1. The intrinsic rate, also called by its inventor Lotka, the true rate of natural increase, is equal to the difference between the intrinsic birth rate (or stable birth rate) and the intrinsic death rate (or stable death rate).
2. Stable, adj. - stability, n. - stabilize, v.
Stable population analysis uses the properties of stable population models to estimate various characteristics of real populations.
6. Stationary, adj. - stationarity, n.