Population growth rates in perfect contraceptive populations

Eventually, world population must cease to grow. In many countries attempts are made to decrease population growth by providing family planning services to all who want to prevent pregnancies. In this paper we use the concept ‘perfect contraceptive population’,¹ — a population in which no unwanted births occur — to derive estimates of the maximum contribution that prevention of unwanted births might make toward attaining a zero rate of natural increase in population.     

The poor as a “perfect contraceptive population” and zero population growth

A goal of the federal family planning program is to enable women to have only those children they want, with priority given to the poor. Is that compatible with the goal of those who want zero population growth? This analysis shows that prevention of all unwanted births to women in low-income families would have yielded completed fertility much above that required for zero population growth.     

Population growth,life-cycle saving,and international differences in steady-state optimal saving rates

Life-cycle savings theories have been a seminal development in analyses of the relationship between rational savings patterns for individuals and the accumulation of wealth or capital at the level of the society as a whole. Applications of the theories in industrialized countries never investigated the significance of large differences in birth and death rates across societies. The strong demographic components of life-cycle saving analysis are here the center of focus. Illustrative general numerical applications of a modified version of the life-cycle approach suggest that mortality differentials comparable to those presently encountered among nations are consistent with very large differentials in steady-state optimal ratios of wealth-to-income. Specific application to Peru of the model estimated by Tobin for the United States indicates that high levels of mortality, current Peruvian birth rates, and Peruvian age-income profiles imply optimal rational savings rates far below those of the United States.     

Declining birth rates and growing populations

Excitement over declining fertility in the Third World needs caution for several reasons. First, it is now too late to solve the world's population problem. Second, the common belief that the birth decline is widespread and is affecting virtually all developing nations goes beyond the data. Third, the notion that birth rates are declining with great speed is not true when the rate is measured against either urbanization or mortality decline. Fourth, a sample of countries indicates that the decline is now slowing rather than accelerating. Fifth, the idea that the declines are due mainly to family planning, and can therefore be assured of continuance in the future, seems unwarranted.Revised version of a paper given at the annual meeting of the American Sociological Association, San Francisco, September 7, 1982.     

The impact of postpartum redundant use of contraception on contraceptive failure rates

Redundant use of contraception occurs when periods of contraceptive use overlap with periods of reduced fecundity, and will downwardly bias estimates of contraceptive failure rates. This paper investigates this bias using calendar data from the Demographic and Health Surveys. The paper presents unadjusted and adjusted 12-month failure rates for each of nine countries. The impact of redundant use on failure rates is generally modest. It tends to be greater in Indonesia, however, where both the incidence and the duration of overlap are relatively large.     

Population growth and air quality in California

Demographers are often interested in the environmental impacts of population growth. I examine the impact of growth specifically on air quality in California. In recent decades, California has suffered from notoriously polluted air and has experienced rapid population growth. Despite the population .growth, air quality actually has improved since the early 1980s due to aggressive regulatory efforts. Using data for 56 counties, I analyze the contribution of population growth to trends in atmospheric emissions of five regulated pollutants from 1980 to 1990, controlling for trends in per capita income and regulatory efforts. The analysis is disaggregated by source of emissions and demonstrates that population growth is strongly associated with some sources of emissions but not with others. Thus, the overall impact of population growth depends upon the composition of production and consumption activities in each county. I also explore whether the trend in number of households predicts better than the trend in number of persons, and whether the impact of population growth depends upon the age structure or source of growth (immigration or domestic increase). Generally, these alternative specifications of population do not improve the models of atmospheric emissions.     

Population growth and economic development

The paper deals with the relationship between the population growth and economic development in Yugoslavia and its republics, covering the period after the Second World War. Yugoslavia is a developing country with a specific demographic and economic structure which makes her unique in Europe. Its territory is comprised of both relatively developed regions where demographic transition is over, and underdeveloped regions with high natural increase of population where the demographic transition is only just beginning. Correlation and regression methods were used to quantify this relationship. The economic development and structural changes are discussed, relating to human factor. An adequate population policy through family planning is stressed as important in obtaining an increased return to scale with a more positive role of demographic factor.     

Crossovers that link populations with the same vital rates

"In this paper, we consider crossovers of demographic density distributions from...populations that have the same fertility and mortality rates. We focus on observed populations and their associated stationary and stable models, and on proportional distributions of persons, births, deaths and reproductive values....Three different populations were selected to represent a range of demographic behavior. Those populations are Japan 1963, a low mortality, low fertility population; Togo 1961, a high mortality, high fertility population; and the United States 1919-1921, a population whose fertility and mortality are intermediate."     

Selection for divergent emigration rates in laboratory populations ofMusca domestica

Summary High and low emigration rates through a laboratory system were selected for in populations of house flies (Musca domestica L.). Emigration consisted of movement of flies from on plastic box to another by way of a connecting tube. Selection was carried out by first dividing a wild population of flies into two lines and then selecting for movement from the box in one line and against movement from the box in the other line. The selection experiment was performed twice. In both experiments a statistically significant difference between the two strains was obtained in three to four generations of selection. In the second experiment, after 5 genrations the mean number of high emigration rate flies emigrating in 1 hour was 4.37 times the mean number of low emigration rate flies and in 24 hours was 2.81 times the number of low emigration rate flies. The second experiment was terminated after 6 generations, but the first experiment was continued for 35 generations. In this case, divergence ceased in roughly 15 generations. The possible relevance of the findings to laboratory population experiments in which spatial discontinuities are included is discussed. This study was supported by a research grant of the National Science Foundation (Environmental Biology GB 4567) to Prof. DavidPimentel. The author wishes to thank Prof.Pimentel for his aid and encouragement.     

Population growth overshooting and trade in developing countries

This paper examines a developing economy using a family-optimization model in which the number of children is a normal good. Trade liberalization generates two effects: the income effect that increases population growth and the gender wage effect that, in the short run, increases, but, in the long run, decreases population growth. With higher income, families invest more in capital if the status of the capital is significant. Because female labor is complementary to capital, higher investment increases the relative wages of women and attracts them from child rearing into production. Ultimately, the population growth falls below the original level.      

Population growth trends in India: 1991 census

The decennial census counted the total population of India at 843.931 million as of the sunrise of March 1, 1991. The total is 160.6 million higher than that of a decade earlier in 1981. The actual census count exceeded by 45 million the official projections for 1991 based on the 1971 census. However, the official projections for the same year based on the 1981 census fell short by 7.6 million only. Most of the observed differences are explained by the slower decline in the fertility levels. The population growth ratepeaked during 1971–81, perhaps in 1972–73 (based on the Sample Registration Scheme data). The average annualexponential growth rate declined marginally to 2.11 per cent (4.5%) after having remained at a plateau for the previous two decades of 1961–71 and 1971–81. At this point in time, the fertility and mortality trends indicate that India will reach the replacement level fertility [Net Reproductive Rate of Unity] by the years 2010–2015. It can be said with a greater degree of certainty that the official target of reaching the replacement level fertility by the year 2000a.d. will not be reached. Based on the 1991 census results, it can be said that India will reach the billion mark by the turn of the century. The World Bank projects a population of 1,350 million by the year 2025a.d., and a stationary population of 1,862 million by the year 2150a.d., assuming that the replacement level fertility [Net Reproductive Rate = 1] in India is reached about the year 2015a.d.     

Population growth and poverty in the developing world

The links between rapid population growth and the absolute poverty currently affecting 780 million people in the developing countries (excluding China and other centrally planned economies) were examined. Absolute poverty is defined as having less than the income necessary to ensure a daily diet of 2150 calories per person ($200 per person a year in 1970 United States dollars). Focus is on poverty and demography in the developing world (defining poverty; income, fertility and life expectancy; demographic change and poverty), effect of poverty on fertility, family planning programs and the poor, and the outlook for the future. Rapid population growth stretches both national and family budgets thin with the increasing numbers of children to be fed and educated and workers to be provided with jobs. Slower per capita income growth, lack of progress in reducing income inequality, and more poverty are the probable consequences. Many characteristics of poverty can cause high fertility -- high infant mortality, lack of education for women in particular, too little family income to invest in children, inequitable shares in national income, and the inaccessibility of family planning. Experience in China, Indonesia, Taiwan, Colombia, Korea, Sri Lanka, Cuba and Costa Rica demonstrate that birthrates can decline rapidly in low income groups and countries when basic health care, education, and low-cost or free family planning services are made widely available.     

Population growth and differential fertility in Zanzibar protectorate

Of the two islands of Zanzibar and Pemba which together comprise Zanzibar Protectorate, the rate of population growth, as shown by intercensal increases, has been appreciably higher in Pemba than in Zanzibar. These differing rates of growth have been due principally to a lower level of fertility among the Afro-Arab population in Zanzibar Island and especially in Zanzibar Town. The exceptionally low fertility of the Afro-Arabs in Zanzibar Town presents a marked contrast to the fertility of the Afro-Arabs in Pemba and in the rural areas of Zanzibar Island, and to that of the Asian population in Zanzibar Town. It may be attributed in part to a high proportion of single, widowed and divorced women in the town and perhaps also to deliberate family limitation among certain sections of the urban population; but it would also appear that physical sterility may be an important factor, though the precise causes of this sterility remain obscure.     

Population aging and endogenous economic growth

We investigate the consequences of population aging for long-run economic growth perspectives. Our framework incorporates endogenous growth models and semi-endogenous growth models as special cases. We show that (1) increases in longevity have a positive impact on per capita output growth, (2) decreases in fertility have a negative impact on per capita output growth, (3) the positive longevity effect dominates the negative fertility effect in case of the endogenous growth framework, and (4) population aging fosters long-run growth in the endogenous growth framework, while its effect depends on the relative change between fertility and mortality in the semi-endogenous growth framework.     

Population growth and social security financing

By allowing the population growth to be flexible, this paper analyzes the effect of a tax reform that involves an introduction of consumption taxation for social security financing. It is found that population growth and labor supply play an important role in determining the effect of the tax reform. If population growth and labor supply are exogenous, then an introduction of a consumption tax for social security financing, with the payroll tax rate being endogenous, decreases the interest rate and increases capital accumulation. However, if population growth and labor supply are endogenous, then an introduction of a consumption tax for social security financing increases the interest rate and reduces capital accumulation. Received: 26 February 2001/Accepted: 26 August 2001     

Population growth with variable family size

"The Sharpe-Lotka continuous time deterministic model of population growth is developed to take account of some possible forms of mother-daughter fertility association....Model specific results relating the intergenerational fertility effect to the long term population growth rate and magnitude are established. The quantitative implications of the theory are illustrated by a consideration of a general bilinear form of A and in this context numerical results illustrating the finite time growth and also the long term distribution of fertility levels in the stable female population are obtained. In particular, it is shown that different fertility specific subpopulations can coexist indefinitely."     

Population growth with variable family size

The Sharpe‐Lotka continuous time deterministic model of population growth is developed to take account of some possible forms of mother‐daughter fertility association, characterised here by a bivariable measure, A. This leads to a linear double integral equation for which, subject to certain conditions, a finite time solution can be found by Laplace transform methods and thus also model specific results relating the intergenerational fertility effect to the long term population growth rate and magnitude are established. The quantitative implications of the theory are illustrated by a consideration of a general bilinear form of A and in this context numerical results illustrating the finite time growth and also the long term distribution of fertility levels in the stable female population are obtained. In particular, it is shown that different fertility specific subpopulations can coexist indefinitely.     

Population growth in Java in the 19th century

Abstract In demographic literature Java occupies a special position. It is the island where in the nineteenth century a 'population explosion' occurred. In other developing countries this took place in the twentieth century. Following the official figures Java had a population size of about 4.5 million in 1815 (Raffles's Census) and 28.5 million in 1900. The result is an extraordinary rate of growth of 2.2% per year. In this paper it is argued that it is impossible to correct the data by adjusting them. A more promising method is to study the factors which are responsible for the demographic situation, i.e. economic conditions, the so-called pax neerlandica and the health situation in the period 1800-1850. This period has been specially studied, because it is crucial for the calculation of population size which is normally based on the 1815 period. It is suggested that Java cannot really claim to be an exceptional case in the period 1800-1850. This means that the growth rate - in line with the estimates of Carr Saunders and Sauvy -has to be estimated (greater accuracy is not possible) as between 0.5% and 1.0); per annum. On the basis of estimates and calculations, the population size of Java may have been somewhere between 8 and 10 millions around 1800, the latter estimate being the more realistic figure. The view that there was exceptionally rapid population growth in Java in the nineteenth century is to an important degree the product of a Europe-centred approach to the history of Java.     

Mortality,marriage, and growth in pre-industrial populations

It has been widely assumed that in pre-industrial European populations postponement of marriage was a major check on fertility, and that marriage was contingent upon access to a livelihood in the form of a homestead or a craft. Death made room for new families, and the age at inheritance might therefore be an index of the age at marriage. High mortality should then mean early marriage and high fertility. When the effect of a uniform increase in the force of mortality on the “natural rate of growth” is estimated quantitatively, it is found that fertility response is of the same magnitude as the change in mortality so that within a wide range mortality differentials alone would not suffice to account for persistent differentials in growth rates. The assumption of a reasonably effective control through the prudential check is thus strengthened.     

Stable, semi-stable populations and growth potential

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.