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.     

Mortality risks,sequential decisions on births,and population growth

The population growth rates implied by parental attempts to be highly certain of having a surviving son for old-age support are investigated. At life expectancies of 40 to 65 years, family-planning “strategies” using contraception are found to imply markedly lower growth rates (1.01.5 percent vs. 2.5 percent) than are both commonly observed and also previously derived by Heer and Smith. In contrast to strategies relying only on sterilization, contraceptive spacing of births permits parents to buy time and information. In particular, they can postpone deciding whether to have another child until they see if their infant son will survive the earliest years of childhood. These results suggest that many less developed countries might achieve a substantial reduction in birth rates, provided that family-planning programs emphasized contraception as well as sterilization and effectively communicated the idea of spacing births. Factors bearing on the range of applicability of the old-age-security hypothesis, and any results and policies derived from it, are also briefly analyzed.     

Childhood mortality,family size and birth order in pre-industrial Europe

Demography - Based on parish registers, demographic histories of Crulai (France), Tourouvre-au-Perche (France), and Geneva (Switzerland) established the childhood mortality experienced by complete...     

Age at baptism in pre-industrial England

The adequacy of English parish registers as demographic sources has been a subject for much debate.¹ Most attention has been directed to the problem of how far the population at large continued to use the sacraments ofthe Established Church in the late eighteenth and early nineteenth centuries, especially in areas affected by urban growth or Nonconformity. But the more general problem of how far the ecclesiastical registers of ceremonies are acceptable substitutes for registers of vital events also deserves some attention.     

The nexus between extreme weather events,sexual violence,and early marriage: a study of vulnerable populations in Bangladesh

Population and Environment - This study aims to explore whether a relationship exists between extreme weather events, sexual violence, and early marriage. We selected two districts in Bangladesh...     

Age at baptism in pre-industrial England

Abstract The adequacy of English parish registers as demographic sources has been a subject for much debate.(1) Most attention has been directed to the problem of how far the population at large continued to use the sacraments ofthe Established Church in the late eighteenth and early nineteenth centuries, especially in areas affected by urban growth or Nonconformity. But the more general problem of how far the ecclesiastical registers of ceremonies are acceptable substitutes for registers of vital events also deserves some attention.     

Widowhood,family size,and post-reproductive Mortality: a comparative Analysis of three populations in Nineteenth-Century Europe

Researchers from a number of disciplines have offered competing theories about the effects oJ childbearing on parents 'postreproductive longevity. The "disposable soma theory" argues that investments in somatic maintenance increase longevity but reduce childbearing. "Maternal depletion" models suggest that the rigors of childrearing increase mortality in later years. Other researchers consider continued childbearing a sign of healthy aging and a predictor of future longevity. Empirical studies have produced inconsistent and contradictory results. Our focus is on the experience of widowhood, which has been ignored in previous studies. We hypothesize that the death of a spouse is a stressful event with long-term consequences for health, especially for women with small children. Data are drawn from historical sources in Sweden, Belgium, and the Netherlands from 1766 to 1980. Postreproductive mortality was highest among young widows with larger families in all three samples. Age at last birth had little or no effect. We conclude that raising children under adverse circumstances can have long-lasting, harmful effects on a mother's health.     

Law, marriage and illegitimacy in nineteenth-century Germany

Abstract Concern arose among legislators in several German States during the first half of the nineteenth century about overpopulation and increasing numbers of the impoverished classes. This led them to pass legislation restricting marriage to those considered by the community authorities as morally and financially capable of rearing a family. Census data at the time of the repeal of these laws indicate the extent to which they succeeded in repressing marriage. Declining illegitimacy which paralleled the repeal, however, suggests strongly that the legislation was far less effectual in limiting reproduction than it was in preventing marriage. Added confirmation of this interpretation is provided by the contrasting nuptiality and illegitimacy patterns of German states with liberal marriage regulations.     

Uncontrolled growth of human populations,geological background,and future prospects

The geological history of the Earth is replete with examples of animals proliferating to numbers that exceeded the ability of their environments to provide support. Enormous numbers and widespread distributions of many animals sometimes have been followed by drastic reductions in numbers of individuals and even by complete extinction of species. Humans of many nations are following the same trend of population growth beyond the ability of resources to insure adequate food, clothing, shelter, safety, and transport and beyond the ability of Earth to accommodate the wastes. Human population is now 5.4 billion, with a present doubling time estimated at about 35 years. Is this uncontrolled proliferation also to be followed by severe reduction or even extinction? If not, how may human population be stabilized or reduced to a level commensurate with resources and waste disposal—more effective contraceptives, increased abortion, high taxes on procreation? An approach more effective than religion or political control may be through better education (increased percentage literacy) that is known to correlate with lower birth rates and increased national income per capita in the about 167 nations of the world. If leadership cannot soon rise to face this situation, human inhabitation of the Earth may become much more complicated in the not distant future.     

Schooling,marriage, and age at first birth in Madagascar

The low school attainment, early marriage, and low age at first birth of females are major policy concerns in less developed countries. This study jointly estimated the determinants of educational attainment, marriage age, and age at first birth among females aged 12–25 in Madagascar, explicitly accounting for the endogeneities that arose from modelling these related outcomes simultaneously. An additional year of schooling results in a delay to marriage of 1.5?years and marrying 1?year later delays age at first birth by 0.5?years. Parents’ education and wealth also have important effects on schooling, marriage, and age at first birth, with a woman's first birth being delayed by 0.75?years if her mother had 4 additional years of schooling. Overall, our results provide rigorous evidence for the critical role of education—both individual women's own and that of their parents—in delaying the marriage and fertility of young women.     

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.     

Population growth rates in perfect contraceptive populations

Abstract 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 mathematics of sex and marriage,revisited

We analyze the problem of modeling marriages in a two‐sex model of population dynamics. We first deal with the problem of incomplete and inconsistent census data and then use a simulator to compare the performance of a variety of marriage functions in modeling births and couples during the ten‐year period between consecutive U.S. censuses. Unlike most empirical methods for comparing marriage functions based on goodness of fit, the differences in the projections of the various functions in our method are of the same magnitude (or even smaller) than the errors between the projected and real data. We observe that for the population of the United States, the harmonic mean function frequently found and used in the literature is a quite poor performer when compared with many other functions in the family we use.     

The temporal relationship of marriage,conception, and birth in Massachusetts

An investigation into the timing of first births in relationship to the date of marriage in Massachusetts confirmed the finding of previous national and local birth timing studies that first births likely to have been conceived before the marriage of their parents constitute a substantial proportion of all first births. The differential frequency of premaritally conceived births among various subgroups appeared to account for the variation noted in the overall timing patterns of first births after marriage. Data were gathered through linkage of certificates of birth of a sample of legitimate first children with the marriage record of their parents. Analysis of the marriage-first birth interval by maternal age and race, type of marriage ceremony, and occupation of the bride and groom were conducted and comparisons with previously published data were made. Separate consideration was given to the frequency and characteristics of those births likely to be premaritally conceived and those likely to have been conceived after the wedding.     

Mortality,past and future

The study of mortality in previous centuries and of the trends in recent decades helps to elucidate some present-day medical problems and to contribute to their solution. The author considers, from a historical and socio-economic point of view, the factors which, during the last 200 years, have influenced the trends of mortality. This analysis indicates the lines along which present research, aimed at reducing mortality and extending expectation of life, should be directed.

Infancy (0–1 year): In backward countries, the whole of infancy is a period of high mortality. In progressive countries, on the other hand, the main reproductive wastage is in the ‘perinatal’ period, that is to say, covering stillbirths and deaths during the first week of life. For example, even in New Zealand, the death risk per day is more than eighty times as high during the first week of life than in the following 358 days.

Historical studies and social class comparisons suggest that further reduction of perinatal mortality is likely to depend on socio-economic, housing and cultural factors rather than on improvements in obstetric skill. Evidence cited by the author indicates that a crucial factor may be to provide expectant mothers with adequate rest during the weeks immediately prior to delivery. In general, research into mortality in infancy is too much bounded by a purely medical point of view whereas a socio-medical approach is needed.

Childhood (1–14 years): There has been an immense reduction in childhood mortality during the last 200 years. Less than 200 years ago the mortality among children aged 1–4 and 5–9 years was thirty-three times, and among those aged 10–14 years twelve times, that of the present day. Future reduction of mortality among children will be primarily a function of social factors and trends.

Adolescence and maturity (15–49 years): One of the outstanding trends of the last 200 years has been a relative increase in tuberculosis mortality among those aged 15–49 years, whereas among children tuberculosis has become relatively less important

as a cause of death. Recently, however, there has been a decline in the relative importance of tuberculosis as a cause of death among the adolescent and mature and, among New York males, it now takes second place to the cardiovascular

diseases. The total mortality of people in this age group has fallen, since the sixteenth century, by 77% for men and 81% for women. No spectacular discoveries are needed to reduce the mortality of this group by a further third; in doing this, control of environment will be the important factor.

Later maturity and old age (50 years and over): In the four centuries since the Renaissance the mortality of people over 50 years of age has been reduced by half. Among the factors contributing to this reduction is a fall in mortality due to tuberculosis. But even cancer, which is popularly supposed to have increased, used to be more common in the eighteenth century than it is now and to appear at an earlier. age. Moreover, there has been a change in the organs most commonly affected. The distribution of the greater proportion of cancer in a given population is a function of living conditions in the broadest sense of the term. Studies of groups exposed to carcinorelevant factors suggest that a high incidence of cancer in one organ is associated with a low incidence in other organs. But on many other causes of death at the older ages far more research is required, especially on the cardio-vascular-renal complex, and on the degenerative joint and bone diseases.     

Age,Period, Cohort and Early Mortality: An Analysis of Adult Mortality in Italy

Changes in adult mortality in Italy for cohorts born between 1882 and 1953 are analysed and interpreted by means of two different statistical models. The first, an Age–Period–Early Mortality (APEM) model, is employed to analyse the possible relationships between adverse conditions during the first 15 years of life and subsequent mortality. It is shown that higher mortality early in life is associated with higher mortality up to age 45 and lower mortality at latter ages. Finally, possible links between the observed decline in early mortality and the evolution of adult mortality are analysed and discussed.     

Mortality rates of elderly Asian American populations based on Medicare and Social Security data

We present sex- and age-specific death probabilities for the elderly of six Asian American subgroups--Chinese, Filipino, Indian, Japanese, Korean, and Vietnamese--based on data from social Security Administration files. We determined ethnicity by combining race, place of birth, surname, and given name. The data source and ethnic determination are the same for deaths and the population at risk, avoiding the problem of noncomparability present when data for the numerator come from vital records and data for the denominator come from census records. We found that death rates for elderly Asian Americans are lower than those for whites, and that socioeconomic differences between subgroups do not translate into like differences in mortality.     

Interrelated family-building behaviors: Cohabitation, marriage, and nonmarital conception

Data from the National Longitudinal Study of the High School Class of 1972 are used to estimate a series of models of entry into marriage, entry into cohabitation, and nonmarital pregnancy. Our models account explicitly for the endogeneity of one outcome as a predictor of another by taking into account both heterogeneity across individuals due to unmeasured factors that may affect all these outcomes and the correlation in the unmeasured factors across processes. We find that these heterogeneity components are strongly and positively related across the outcomes. Women who are more likely to cohabit, marry, or become pregnant while unmarried are also more likely to do each of the others. Although black and white women differ in the likelihood of these behaviors, the interrelations of the behaviors are quite similar across groups.