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Biomedical subjects

A J Coale

Publications and source records attributed to A J Coale.

At least 19 recordsLinked to original sources
PubMed1994

Five decades of missing females in China.

This paper seeks to explain the dearth of females in the population of China in cohorts born from the late 1930s to the present. We demonstrate that in virtually all cohorts, the shortage of females in comparison with males is revealed when the cohort is first enumerated in a census. Subsequently it barely changes, an indication that female losses occur very early in life. Using the high-quality data from the censuses and fertility surveys in China, we show that many of the births of the girls missing in the censuses were not reported in the surveys because they died very young. The incidence of excess early female mortality (probably infanticide) declined precipitously in the Communist period, but not to zero. The recent escalation in the proportion of young females missing in China has been caused largely by rapidly escalating sex-selective abortion.

Abortion, Legal↗
PubMed1992

Age of entry into marriage and the date of the initiation of voluntary birth control.

It is widely known that modern economic development has been accompanied by the initiation and spread of effective limitation of fertility, and that generally the populations which experienced development at a late date also had a belated reduction in childbearing. Here a surprising relation is found between (and within) broad regions: the areas in which traditional age of entry into marriage was late were the areas in which marital fertility was reduced first.

Adolescent↗
PubMed1991

The effect of age misreporting in China on the calculation of mortality rates at very high ages.

When mortality rates by age are calculated from recorded deaths and enumerated populations, rates at higher ages are typically in error because of misstated ages. Mortality rates for China in 1981 have been calculated from the number of deaths in 1981 in each household recorded in the 1982 census, and from the census population back-projected one year. Because age was determined from date of birth, and because persons of the Chinese culture have very precise knowledge of date of birth, the mortality rates even at high ages should be unusually accurate. This expectation is fulfilled for most of China, but severe misreporting of age is found in a province that contains a large minority of a non-Han nationality, which lacks precise knowledge of date of birth. Although the province contains only 1.3% of China's population, male death rates above age 90 for all of China are distorted seriously by the erroneous data from this location.

Aged↗
PubMed1990

Age patterns of mortality for older women: an analysis using the age-specific rate of mortality change with age.

"In this paper we propose a mortality measure that seems useful in analyzing age patterns of death rates. The measure, which will be denoted by k(x), indicates the proportional increase or decrease with age in the risk of death at a given age x, and is called the age-specific rate of mortality change with age." Estimations are presented for women in 10 countries. "Eight of the selected sets of data are for developed nations in the 1960s and 1970s, and the other two sets of data, for Taiwan, 1931-35, and for Germany, 1910-11, represent relatively high mortality. For France and West Germany, three different periods are included for an investigation of cohort effects on the observed age patterns." Other mathematical models of age-specific mortality rates are discussed and compared. (SUMMARY IN FRE)

Adult↗
PubMed1985

Calculation of age-specific fertility schedules from tabulations of parity in two censuses.

The mathematics of stable populations recently has been generalized to cover populations with time-varying fertility and mortality by a modification incorporating the sum of age-varying growth rates in place of the fixed growth rate of a stable population. Equations that characterize nonstable populations apply to any cohort-like phenomenon with a measurable property that cumulates gains or losses through time. In particular, the equations fit the relation between a population's average parity at a given age and age-specific fertility rates previously experienced at lower ages. Techniques devised to derive an intercensal life table from single-year age distributions in two censuses are adapted to estimate accurate intercensal fertility schedules from distributions of parity by age of woman in two censuses. Birth-order specific fertility schedules are also estimated.

Adolescent↗
PubMed1984

The demographic transition.

Demographic transition is a set of changes in reproductive behavior that are experienced as a society is transformed from a traditional pre-industrial state to a highly developed, modernized structure. The transformation is the substitution of slow growth achieved with low fertility and mortality for slow growth maintained with relatively high fertility and mortality rates. Contrary to early descriptions of the transition, fertility in pre-modern societies was well below the maximum that might be attained. However, it was kept at moderate levels by customs (such as late marriage or prolonged breastfeeding) not related to the number of children already born. Fertility has been reduced during the demographic transition by the adoption of contraception as a deliberate means of avoiding additional births. An extensive study of the transition in Europe shows the absence of a simple link of fertility with education, proportion urban, infant mortality and other aspects of development. It also suggests the importance of such cultural factors as common customs associated with a common language, and the strength of religious traditions. Sufficient modernization nevertheless seems always to bring the transition to low fertility and mortality.

Birth Rate↗
PubMed1984

Life table construction on the basis of two enumerations of a closed population.

The author demonstrates that an accurate detailed life table that represents average mortality experience between two censuses can be constructed if the censuses provide accurate records of the single-year age distribution of a closed population. This life table can begin at age zero if accurate data on the annual number of births during the inter-censal period are available; otherwise the first age in the life table must equal the duration of time between the censuses. "The estimation technique involves the calculation of the number of persons attaining each age during the period between the censuses and the determination of the average rate of increase in the number at each individual age. The success of the technique comes from the use of interpolation to calculate how many in each cohort attain each exact age the cohort passes through between the censuses." The estimation technique is tested using two alternative methods of interpolation. Some illustrations based on data for Sweden and China are included.

Age Distribution↗
PubMed1983

Recent trends in fertility in less developed countries.

The rate of increase of population in less developed countries accelerated rapidly from 1850 to 1960 because of a rapid decline in mortality while fertility remained high. In the 1960's, the birth rate as a whole began to decline more rapidly than the death rate--very rapidly in some populations, most notably that of China, more gradually in others, and not at all in some of the poorest populations. The momentum of growth implies continued increase in populations for several decades even in countries where fertility has fallen the most, and very large additional increases where there has been no decline in the rate of childbearing.

Age Factors↗
PubMed1982

A reassessment of world population trends.

This reassessment is limited to observations concerning trends in mortality and fertility and concerning longrun prospects for population growth. Recorded changes in mortality are compared with 3 projections made many years ago. Projections of European mortality made in 1941-42 understated by a wide margin the actual increase in expectation of life because of unforeseen technological changes in the prevention and cure of fatal disease. On the other hand, a projection made in 1955 for India, foreseeing a rapid rise in the 1950s and slower progress later on because of the exhaustion of the easier gains, appears to have been accurate and also to depict the prospects in other populations of relatively high mortality and low income. A different projection of life expectancy in Mexico was also quite close to actual changes in Mexican mortality; it was based on a universal curve constructed to represent how life expectancy rises, increasing ever more slowly as it approaches an upper limit. This curve (1 for each sex), constructed for projection of Mexican mortality, is employed as a standard of comparison for mortality changes in many countries. A number have followed the standard for females very closely for more than 3 decades; in developed countries, male life expectancy has generally fallen short of the standard. The almost universal low fertility in developed countries contrasts with the great diversity of levels and trends of fertility in developing countries, some of which retain undiminished high fertility and others of which have recently attained rates of childbearing as low as in the developed areas. Instances of surprisingly little change and surprisingly rapid change in fertility are described. In the future, growth of populations of developed countries will probably be slight; the future rate of increase in the developing areas depends on the unpredictable timing and pace of childbearing reduction in populations where fertility remains high. In the long run, world population growth may resume its typical pattern of moderate growth interrupted by catastrophic setbacks.

Australia↗
PubMed1981

[Robust estimation of fertility by the use of model stable populations].

"If we know the proportion of population under 15 years of age, the probability of newborns to reach 5 years of age and the rate of growth of that population, by means of a very simple procedure we can estimate the birth rate, the growth reproduction rate and the total fertility rate through the appropriate use of stable population models. Even if the real population is far from being a stable population the estimates are very little affected, which shows the robustness of the procedure." (summary in ENG)

Birth Rate↗