Popul Stud (Camb). 1971 Jul;25(2):235-54. doi: 10.1080/00324728.1971.10405800.
Abstract Starting from the definition of a Malthusian population given by Alfred J. Lotka, the author recalls how the concept of stable population is introduced in demography, first as a particular case of stable populations, and secondly as a limit of a demographic evolutionary process in which female age-specific fertility rates and age-specific mortality rates remain constant. Then he defines a new concept: the semi-stable population which is a population with a constant age distribution. He shows that such a population coincides at any point of time with the stable population corresponding to the mortality and the fertility at this point of time. In the remaining part of the paper it is shown how the concept of a stable population can be used for defining a coefficient of inertia which measures the resistance of a population to modification of its course as a consequence of changing fertility and mortality. Some formulae are established to calculate this coefficient first for an arbitrary population, and secondly for a semistable population. In this second case the formula is particularly simple. It appears as a product of three terms: the expectation of life at birth in years, the crude birth rate, and a coefficient depending on the rate of growth and for which a numerical table is easy to establish.
摘要 从阿尔弗雷德·J·洛特卡给出的马尔萨斯人口定义出发，作者回顾了稳定人口的概念是如何在人口学中引入的，首先作为稳定人口的一个特例，其次作为女性特定年龄生育率和特定年龄死亡率保持不变的人口演化过程的极限。然后他定义了一个新概念：半稳定人口，即具有恒定年龄分布的人口。他表明，这样的人口在任何时候都与对应于该时刻的死亡率和生育率的稳定人口一致。在本文的其余部分，展示了如何使用稳定人口的概念来定义惯性系数，该系数衡量人口对生育和死亡率变化导致的其自身进程改变的抵抗力。建立了一些公式，首先用于任意人口，其次用于半稳定人口来计算这个系数。在后一种情况下，公式特别简单。它是三个项的乘积：出生时预期寿命（以年计）、粗出生率和一个取决于增长率的系数，后者易于建立数值表。
