Fertility Fluctuations Research Articles

Socialist institutions and family wealth flows reversal: an assessment of post-revolutionary Chinese rural fertility.

The study examines a hypothesis explaining the historical impact of socialist agricultural institutions on Chinese rural fertility. The implementation of collective agricultural management and socialization of traditional family relations under various types of socialist rural institutions are shown to have affected Chinese peasants' fertility by changing the “intergenerational wealth flows” situation. To take into account the extraneous effects of economic conditions and family planning policy on rural fertility, statistical models are constructed which compute residual fertility fluctuations unexplained by these factors. By comparing the unexplained fluctuations of rural fertility with institutional changes that in varying degrees weakened the traditional sociopolitical and economic functions of family, we assess our hypothesis on the relation between macro institutional changes and fertility behavior of rural families.

SOCIALIST INSTITUTIONS AND FAMILY WEALTH FLOWS REVERSAL: An Assessment of Post-Revolutionary Chinese Rural Fertility

The study examines a hypothesis explaining the historical impact of socialist agricultural institutions on Chinese rural fertility. The implementation of collective agri cultural management and socialization of traditional family relations under various types of socialist rural institutions are shown to have affected Chinese peasants' fertility by changing the "intergenerational wealth flows" situation. To take into account the extraneous effects of economic conditions and family planning policy on rural fertility, statistical models are constructed which compute residual fertility fluctuations unexplained by these factors. By comparing the unexplained fluctuations of rural fertility with institutional changes that in varying degrees weakened the traditional sociopolitical and economic functions of family, we assess our hypothesis on the relation between macro institutional changes and fertility behavior of rural families.

Exploring theoretical frameworks for the analysis of fertility fluctuations.

Analysis of scientific debate on the determinants of procreational choice leads the author to identify four main decisional logics: primary adaptation, economic rationality, norm internalization and identity reinforcement. Revisiting the classics supports the hypothesis of a bipolarity of strategical principles governing fluctuating reproductive behaviour. In particular, dialectics between the two endogenous strategies — economic rationality and identity rationality — suggests the use of the Volterra-Kostitsin predator-prey model as a metaphor to account for fertility waves.

A length class model of the population dynamics of the Antarctic Krill Euphausia superba dana

In a location-independent simulation, Krill frequency and weight are modelled in 0.5 mm length classes. Population dynamics are defined by time- and length-dependent birth, growth and death rates. In a steady state (constant death rate of 98.7% p. a.) Krill frequency and weight oscillate by a factor of 32 and 3, respectively. Larval catch curves from German Antarctic Expeditions and published mortality rates for older Krill suggest a hyperbolic form of the survival function with age (i.e. mortality decreases with increasing body length). A Krill fishery can be simulated indirectly through manipulation of the mortality rate or through direct elimination of individuals. For example, a complete elimination of the upper length classes does not lead to extinction even if performed each year before the spawning season, as long as the size at fist capture is greater than 45 mm. The Antarctic Krill seems to be a classical example of r-selection with its high fertility, high mortality and large stock fluctuations.

An analysis of variations in U.S. Fertility and female labor force participation trends: A reply

This study is based on time series data from 1947-1977 on fertility and female labor force participation, and examines (a) the effects of male relative income and female earnings on the level and timing of fertility and female labor force participation, and (b) the relative importance of variations in relative income and female wage rates in explaining the fluctuations in both fertility and female labor supply. The results suggest that relative income exerts a significant positive effect on fertility and a negative effect on female work effort. However, female wage rates appear to be the dominant factor in explaining variations in fertility and female labor force participation over the past two decades, with increases in female earnings leading to both depressed fertility and increased labor force participation of women.

Population waves and fertility fluctuations: Social security implications

The demographic consequences of periodic movements in fertility rates are explored. Different types of periodic fluctuations are examined and incorporated into long range population projections. In some cases the resulting population waves can have a profound impact on a national social security system. These impacts are illustrated numerically in the context of the Canadian situation.

Short-run fluctuations in fertility and mortality in pre-industrial Sweden

This paper describes and interprets annual Swedish data from 1750 to 1869 on weather, harvests, real wages, birth rates, and death rates using vector autogression. Impulses due to unexplained increases in wealth, whether this occurred through increased real wages, improved agricultural yields, or warmer winters, led in the short run to increased fertility and decreased infant and non-infant mortality, and hence to increased rates of population growth. Unexplained or unanticipated fluctuations in infant mortality led to replacement cycles in fertility within one to three years, although only a negligible cumulative effect on fertility persisted after five to ten years. Fluctuations in deaths among persons older than one year evoked a fertility response several years later, but this replacement response persisted after more than a decade. Although vector autoregression is not designed to account for long-term trends and their consequences, the interrelationships found here among exogenous weather shocks and fluctuations in economic conditions and demographic rates provide support for the homeostatic mechanisms hypothesized by classical economists and discussed by Malthus. The methodology of vector autoregression appears useful for studying historical series on climatic, economic and demographic variables where we do not yet have a sufficient theoretical foundation for specifying and estimating structural models.

An analysis of variations in U. S. fertility and female labor force participation trends

Abstract This study is based on time series data from 1947–1977 on fertility and female labor force participation, and examines (a) the effects of male relative income and female earnings on the level and timing of fertility and female labor force participation, and (b) the relative importance of variations in relative income and female wage rates in explaining the fluctuations in both fertility and female labor supply. The results suggest that relative income exerts a significant positive effect on fertility and a negative effect on female work effort. However, female wage rates appear to be the dominant factor in explaining variations in fertility and female labor force participation over the past two decades, with increases in female earnings leading to both depressed fertility and increased labor force participation of women.

Low Fertility and Liberal Democracy in Western Europe

During the past two decades, fertility decline in Europe has been precipitous, and there is an increasing convergence among countries toward a level at which the replacement of the population in the long run is no longer assured. For most of the 1970s, both German Republics and Luxembourg have had more deaths than births each year, and, as a leading demographer asserted at the end of 1978, If the present trends should persist, the population of Europe as a whole and of the USSR would begin to decline at the turn of the century and the US population would stop growing in about 2015. ' Several countries that still have a positive balance between births and deaths are in that position only because they have a relatively large number of women in the prime reproductive years and not because their fertility per woman is high enough to ensure replacement. At the present time, moreover, demographers are increasingly of the opinion that changing patterns of marriage and family formation are such that a spontaneous upturn in fertility, sufficient to assure replacement of the population, is unlikely.2 Low fertility and declining rates of population growth pose difficult problems of adjustment for government and society: changes in age structure and a growing number of elderly dependents-especially those at the oldest ages-strain the financial bases of social security systems; aging work forces introduce unwanted rigidities into the operation of labor markets; depopulation of rural areas calls into question the shape of regional development policies. While many Western economists nowadays appear to believe that economic growth is possible under conditions of population stagnation, albeit at a lower level than in the recent past, they are much less certain about continued growth after a population starts to decline.3 In addition, fluctuations in fertility bring with them discontinuities and problems of accommodation as cohorts of different sizes work their way through the age structure, causing waves of ex-

Demographic Forecasting and the Easterlin Hypothesis

A model for forecasting fertility fluctuations in a population that is highly urbanized has low mortality and contracepts effectively is described. Based on the research of Easterlin which questions whether fertility and age distribution can be forecast separately it exploits a strong observed association of age-specific fertility and population size and structure. Population size and age structure are hypothesized to affect relative income through the mechanisms of pressure on limited resources. It is the comparison of income with expectations or aspirations that matters in the relationship. There will thus be a positive relationship between fertility and relative income and a negative one between age group size and income. Taken together these suggest that fertility and cohort size should be inversely related; which association forms the basis for the model. This is contrary to the usual assumption for forecasting in the U.S. i.e. that fertility rates are independent of population size and age structure. Though the model has not yet been well tested and still depnds on many subjective decisions it does help to identify the long run level of fertility by placing current experience in perspective. The ability to forecast fluctuations in fertility and age structure will demographers believe be increasingly important and will have major policy implications. When applied to the U.S. the model indicates that current fertility is only temporarily low and an upturn should occur after 5 or 10 years.

An Economic Framework for Fertility Analysis

The standard formulation of the microeconomic theory of fertility, which emphasizes the demand for children and, to a lesser extent, the costs of fertility control, is too limited in its scope for use by most demographers and sociologists. The approach advanced in this paper adds to the usual theory a more explicit and formal treatment of the production of children, including the possibility of shifts in production independent of demand conditions. This more comprehensive framework is compared with the usual approach in the analysis of several empirical problems-non-marital fertility, premodern fertility fluctuations and differentials, and the secular fertility decline-and is shown to be better suited for incorporating the concepts and hypotheses of noneconomists along with those of economists.

The natural regulation of buffalo populations in East Africa: II. Reproduction, recruitment and growth*

SummaryAspects of the seasonality of breeding, age‐specific fertility, and growth were studied in a sample of animals collected from the Serengeti buffalo population, and compared with two populations in Uganda. Fluctuations in fertility and recruitment were studied by the use of regular aerial photographic samples of herds in the Serengeti. The fluctuations in fertility rate were not related to density and hence could not have regulated the population.Buffalo show a pronounced seasonality in births which is correlated with the quality of ingested food and with rainfall. Since the female has a considerably higher food requirement during late pregnancy and lactation, nutrition is probably an important factor determining this seasonality. Conception does not appear to be influenced by nutrition, for the quality of food remains high throughout the rainy season prior to and during the period of conception. Growth rate, age of first ovulation, and age of sexual maturity do not appear to differ between the Serengeti and Uganda populations. Although there is little difference in fertility between these populations, as measured from the collected samples, little weight can be placed on this evidence, for large fluctuations in fertility can take place from year to year within a population. The fluctuations in the Serengeti population do not appear to be correlated with rainfall, and it is possible that they are random. Fluctuations in recruitment from year to year are also observed. Two sample areas over 100 km apart but within the same population show parallel fluctuations suggesting a similar external influence on the size of the recruitment. This recruitment is not correlated with population size but it may be related to rainfall. Underweight calves at birth have been recorded and this may have been caused by the undernutrition of pregnant females during the dry season through a combination of poor food supply and the demands of the previous lactation.

The World Fertility Survey: An International Program of Fertility Research

This 5-year world fertility survey was begun in mid-1972 to assess the current status of human fertility throughout the world and improve demographic data collection. Individual countries were informed and the participating countries had studies undertaken to acquire information from 3 levels: 1) the community level; 2) the household level; and 3) the individual respondent selected for detailed interview. The contents of the interview are described and provisions for quality control and processing are briefly described. The organization of the World Fertility Survey (WFS) is broken down into International groups (Permanent Advisory Committees and WFS Central Staff) national organizations for each country and training and timetable groups. The origins and history of the WFS are described from the proceedings of the biennial conference in 1971 of the International Statistical Institute. The association of the WFS with the African Census Program for 1972-1975 will assist the African program with fertility aspects of its census and thereby include Africa in the WFS. The Economic Commission for Europe (ECE) is studying 12 countries in Europe to find causes for postwar fluctuations in fertility and to estimate future trends; the ISI is engaged in discussions with the ECE for mutual interest studies. A pilot study will begin in Fiji in early 1974.

Short-term fluctuations in fertility and economic activity in Israel

Abstract This paper investigates the relation between fluctuations in fertility and in economic activity in Israel over the period 1950–1970. The paper opens with some comments on the theoretical basis for expecting procyclical behavior of fertility. This is followed by analysis of annual data of total fertility, unemployment, GNP and an index of industrial production. Total fertility tends to respond to the cyclical indicators among Jews from Europe and America, those born in Israel and those from Asian and African countries, but the response is larger among the former. Cyclical response can be discerned also in the fertility of the non-Jewish population. The performance of the alternative cyclical indicators is compared. Some examination of data on marriage suggests that the cyclical response of birth is not just a reflection of the cyclical response of marriage. In the annual data there is a tendency for.Jewish fertility to be more related to the contemporaneous cyclical indicator than the lagged indicator, while the reverse is true for the non-Jewish population. Examination of quarterly and monthly data for a shorter period corroborates this finding. Many factors are involved in determining the lag between an observed cyclical indicator and observed birth; it is being conjectured that the prevalence of abortions in the Jewish population is one contributing factor to the difference in the lag between.Jews and Arabs.

The Character of Modern Fertility

One characteristic shared by all modern indus trialized and urbanized nations is low fertility. From different initial levels, beginning at different times, the birth rates have declined slowly in some industrialized and urbanized countries and rapidly in others, but have now settled down on a common low plateau a little above what is required for replacement. The regulation of fertility has been achieved by widely variant strategies, involving different combinations of nuptiality control, contraception, and abortion. In every case the small family size has represented the intent of the individual couple and not the guidance of government or church. The explanation of fertility decline advanced here places stress on a normative change in the relationship between parents and children under conditions of declining mortality and urban economic development. Although the fertility of modern industrialized and urbanized nations is not expected to change much in the long run, these societies will probably have difficulty in avoiding costly fertility fluctuations and in keeping the reproductive goals of individual couples from eventuating in too little or too much population growth.

Births, Marriages, and Business Cycles in the United States

Births, Marriages, and Business Cycles in the United States

Periodic fluctuations of soil fertility, crop yields and of responses to fertilization effected by alternating periods of low or high rainfall

Periodic fluctuations of soil fertility, crop yields and of responses to fertilization effected by alternating periods of low or high rainfall

Differential Fertility in Chicago, 1920-40

Total fertility rates from 1920 to 1940 and nuptial fertility rates for 1930 are presented, by nativity and color, for five socio-economic groups in Chicago. The so-called "postwar" developments in earlier age at marriage and in the convergence of socio-economic differentials in fertility apparently began almost two decades ago when the upswing in births first began. In the context of other studies, the findings also indirectly suggest that fluctuations in total fertility and nuptial fertility followed different patterns during the depression and that marraige rates probably decreased relatived more among low-than among high-status groups.

Fertility and Climatic Adaptations in Siberian Grasshoppers

Summary1. The number of egg-tubes and the number of eggs in each tube varies in accordance with the food and the climatic and microclimatic conditions of each habitat. The majority of Siberian grasshoppers have adaptations in the ovaries which enable them to take full advantage of the available heat.2. In the species possessing 10 or more egg-tubes, their number varies in different parts of the distribution area. It decreases towards the centre of the area with increasing warmth and dryness, and increases towards the colder and more humid margins of that area (e.g., in the Far East and in Western Europe).3. The potential fertility is more or less stable in different species of grasshoppers, and in the species studied it fluctuates between 84 and 388 eggs per female.4. There is no correlation between the potential fertility and the abundance of the species in nature, for the greatest fertility is met with in those species which occur but rarely. The injurious (i.e., very numerous) grasshoppers have a medium, or somewhat less than a medium, potential fertility.5. The actual fertility is greatly dependent on the environment and has a wide range of fluctuation.6. Lack of food in reservations was observed to lower the fertility of grasshoppers by 30–40 per cent. The parasites (Blaesoxiphaspp.,Mermisspp.) greatly reduce the degree of fertility of the Siberian grasshoppers. However, the percentage of infestation by these parasites is low, but in the reservations it is somewhat higher than outside. Thus, the actual fertility in reservations is rather lower than outside.7. The outbreaks of the Siberian grasshoppers are determined by the climatic and microclimatic conditions. The fluctuations in fertility never have any real importance in causing the outbreaks. Lack of food, parasites, predators and diseases are of minor importance; among the latter the main factors are the diseases of the egg-pods, which again depend on the microclimate.