中国人口年龄结构变动对出生率的影响研究

本文利用相关年份的《中国统计年鉴》和人口普查数据,根据粗出生率与总和生育率的关系与特征,构建了人口年龄结构系数及其对粗出生率变动影响的贡献率指标,分析了建国以来人口年龄结构变动对出生率的影响。研究发现：1949—1979年,人口年龄结构变动对出生率的影响很小;1980—1993年,人口年龄结构变动对出生率的影响迅速上升,年龄结构的贡献率增大;1994—2008年,人口年龄结构变动对出生率的影响趋于下降,人口惯性势能在减弱;2009—2011年,受80—90年代出生高峰的影响,人口年龄结构变动对出生率的影响再次凸显,年龄结构的贡献率迅速增大。从年龄别生育率逐年下降的特点,也可以证明近年推动我国人口增长的力量主要是由于年龄结构带来的惯性增长。     

Population statistics] as of July 1, 1998

This article presents estimates of relevant population numbers and vital rates in Thailand as of July 1, 1998. Utilizing the standard demographic techniques of analysis, the estimates provided are assured to be the most accurate demographic estimates possible. Total population was estimated at 61,143,000. Estimates by sex, locales, region, and by age group are included. In addition, the crude birth rate per 1000 population was estimated at 18.7; the crude death rate per 1000 population was 6.5. For the natural growth rate the estimate was at 1.2%, and the infant mortality rate was 25.0 per 1000 live births. In terms of life expectancy at birth, the estimate for males was 69.9 years, while for females it was 74.9 years. Additional years in life expectancy at age 60 were 20.3 years for males and 23.9 years for females. The total fertility rate per woman is 1.98, and contraceptive prevalence is 72.2%. The demographic data will be disseminated to Thai and international population researchers and planners.     

A close look at the demography of Afghanistan

The first survey designed to allow estimates of the demographic characteristics of Afghanistan's sedentary population was conducted during the period 1972-1974. Our analysis of these data, based on recently developed techniques for handling imcomplete or inaccurate data, suggests that this population lives under conditions that are extreme when judged by modern standards. Marriage is early, especially for females, and universal. Marital fertility conforms to a pattern of natural fertility and total fertility is high. The birth rate is among the highest in the world today, and the expectation of life at birth is among the very lowest. Mortality is lower in urban areas than in rural areas, whereas total fertility is approximately the same in both. Our estimates of fertility and mortality imply stable populations which match closely the observed age distributions for both the rural and urban areas.     

Estimation of vital rates by means of monte carlo simulation

Monte Carlo simulation has been used to estimate age-specific fertility and mortality rates for a small population,the French-derived isolate of Northside on St. Thomas, U. S. Virgin Islands. Estimates were based on data collected in a household census and genealogical survey and on birth, death, and marriage records for the years 1916to 1966. During this 50-year period (in which the population size increased from 202 to 657), the numbers of births and deaths were too, small to estimate age-specific rates directly, and in addition, death registration was incomplete. Mortality rates were estimated using a simulation program in which mortality was the only stochastic variable. A model mortality schedule was chosen which most accurately reproduced the growth pattern of the population over the 50-year period. To estimate fertility rates, a more complex simulation model was used in which fertility, nuptiality, and mortality were random variables with probability distributions. Preliminary estimates of fertility were made from the birth records and used as input to this simulation program. Birth probabilities were adjusted empirically from one set of simulation runs to the next, until population growth rates, as well as other demographic characteristics, were similar in the real and simulated populations. The birth rates which produced the best fit to the real population data were taken as the estimated age-specific fertility schedule. To reproduce the real population age structure more closely, secular changes in birth probabilities were applied.     

Empirical analysis of the contribution of age composition to population growth

The method of decomposition is applied to rates of natural increase in order to elucidate the role played by age composition in the growth of populations. A population’s age distribution and fertility schedule are contrasted to those in a "stationary" population having the same mortality rates and having a fertility schedule equal to that of the observed population divided by its net reproduction rate. In this manner it is shown that about one-quarter to one-third of the growth of most current high-growth populations can be attributed to non-stationarity of their age distributions. This fraction will rise, as it has in most industrialized countries, if fertility is reduced and age distributions become middle-heavy. In projections of the 1963 Venezuelan female population with fertility rates declining by 20/0 and 1% annually, more than half of the growth (in numbers) that occurs prior to zero-growth attainment is contributed by non-stationarity of its intervening age distributions.

     

A simulation of the impact of changes in age at marriage before and during the advent of industrialization in England

Summary The quantitative significance of changes in age at marriage on family size is assessed by applying a simple simulation model of family reproduction, using data broadly related to England in the period 1700-1850. Within this context, the impacts of parity-specific infant mortality, and an association between age at marriage and potential fertility are considered. The evidence concerning variations in marriage and mortality distributions over the period in question is examined and linked to the simulation results to produce some tentative conclusions relating to the impact of changes in the distribution of age at marriage on the birth rate and rate of population growth and to an assessment of such changes as an homeostatic adjustment mech-anism. In particular, it is argued that age at marriage played no more than a secondary role in the English demographic revolution.     

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.     

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.     

Analysing open birth interval distributions

Summary This paper began with the recognition that open birth interval distributions are analogous to age distributions. It then became clear that closed birth interval distributions are, somewhat more loosely, analogous to mortality schedules, and that the relationship between open and closed birth interval distributions could be explored by imitating the formal demography of mortality and age distribution. Pursuing this programme, we develop the formal demography of open and closed birth interval distributions and show that under certain assumptions open interval distributions may be used to estimate closed interval distributions, just as age distributions may be used to estimate mortality. An illustrative application to Indonesian data is given.     

Estimation Of The Birth Rate For The Congo Through Nonconventional Techniques

This paper attempts to produce a set of alternative estimates of birth rates for the Congo and for its main regions through nonconventional techniques. The main body of data used for this purpose is supplied by the demographic survey undertaken during 1955-57. Two types of information on fertility are produced by this survey: (1) births to women by age during the 12 months preceding the survey and (2) children-ever-born to women by age. The available data, while reliable in certain respects, are deficient in others. Thus, the reports on children born during the year preceding the survey are acceptably accurate for the children who have survived but are insufficient for the children who have died.The task was to make the best possible use of various reliable pieces of information directly or indirectly related to fertility, in order to produce some reasonably acceptable estimate of birth rate. One procedure consisted of correcting the reported birth rate for the omission of infant deaths; another procedure involved the adjustment of the reported birth rate with reference to the mean parity of women. In addition to these, an estimate of birth rate was derived by means of stable population technique from the proportion of children under 5 years of age.Three sets of estimates of birth rate, then, have been produced. They yielded a high agreement for the country as a whole, as well as for the provincial and district levels. These estimates were then compared with the proportion of childless women and the proportion of children-the latter having been derived from the records of "continuous registration of inhabitants," a source of information which is completely independent of the demographic survey of 1955-57. Again, a reasonable agreement has been found among all these estimates.Statistical evidence examined in this paper supports a birth rate of about 45 per 1,000 for the Congo. The analysis reveals a high regional variation in birth rate: from 20 per 1,000 (Bas Uele) to 60 per 1,000 (Kivu). This variation is consistent with the variation in sterility level as evidenced by the proportion of women never having had a live birth. The proportion of childlessness varies from 5 percent (Kivu) to about 40 percent (Bas Uele) for women past child-bearing age.     

俄罗斯人口发展状况及对中国的启示

本文利用俄罗斯的历史人口数据,对俄罗斯人口数量和结构变动状况进行了分析,并对俄罗斯三次人口转型中的社会经济情况变化对人口变动状况的影响进行了分析。结果表明,俄罗斯的人口出生率下降很快,人口死亡率升高,总和生育率已远低于替代水平,因此人口自然增长率迅速下降,总人口数长期处于下降通道,出生预期寿命不增反降,特别是男性出生预期寿命远低于女性出生预期寿命。在推动人口增长的社会经济相关措施实施后,俄罗斯人口数量仍不能增加,这对目前总和生育率已经很低的中国有一定的借鉴意义。     

Effect of mortality change on stable population parameters

The stable population model is used to establish formulas expressing the effects of mortality change on population growth rates, birth rates, and age composition. The change in the intrinsic growth rate is shown to be quite accurately approximated by the average decline in age-specific death rates between age zero and the mean age at childbearing in the stable population. This change is essentially independent of the initial level of fertility in the population. Changes in birth rates and age composition are shown to be simple functions of the age pattern of cumulative changes in mortality rates relative to an appropriately defined “neutral” standard.     

Age-parity-specific birth rates and birth probabilities from census or survey data on own children

The ‘own-children’ method is a census- or survey-based reverse-survival technique for estimating age-specific birth rates for years previous to enumeration. In this paper it is extended to estimate birth rates and birth probabilities by parity as well as by age. The refined method is tested for accuracy by comparing ‘own-children’ estimates of age-parity-specific birth probabilities for the United States in 1969 with parallel estimates obtained by the method used in Vital Statistics of the United States. The ‘own-children’ estimates give relatively lower values at ages 15-19 and higher values at ages above 40, but compare well in between. The discrepancies are probably due mainly to adoption of illegitimate children of young mothers by older women. The ‘own-children’ estimate of the total fertility rate is very close to the published vital statistics estimate.     

The determinants of early fertility decline in Texas

This study examines the determinants of fertility control in a frontier population made up largely of German-Americans during the years from 1850 to 1910. The analysis employs a complex register of population constructed from census enumerations, civil and ecclesiastical vital registration, and tax assessment rolls. The article begins with a series of bivariate analyses with cohort of mother’s birth, religion, ethnicity, and husband’s occupation determining marital fertility. The second half of the paper presents a multivariate model of the determinants of fertility using these and other demographic characteristics as independent variables. The conclusions emphasize the importance of the overall trend toward fertility decline in the United States, as well as the role of religion and of occupational differences, in determining changes in fertility behavior in the population of Gillespie County, Texas.     

Population statistics] as of July 1, 2000

This Mahidol Population Gazette presents Thailand's population and demographic estimates as of July 1, 2000, using the standard techniques of demographic analysis. The paper provides estimates of Thailand's total population, population by sex, population in urban and rural areas, population by region, and by age group. In addition, figures of crude birth and death are listed per 1000 population, natural growth rate, and infant mortality rate per 1000 live births, male and females' life expectancy at birth and at age 60, total fertility rate, contraceptive prevalence rate. The number of the aged population in 2020 is also presented. Presented in a bar graph is a population pyramid for Thailand in the year 2000, illustrating male and females' age and year of birth.     

The achievements in family planning work in Rudong County as suggested by the data of the Fertility Survey]

A 15% random sampling from Rudong County was recently taken to survey fertility rates. 1153 primary units were chosen, which included 160,832 people. Among this group were 57,050 women aged 15-67 years. Topics surveyed included: marriage, birth, contraception, and population structure. Rudong County, among the earliest counties in China to begin the work of birth control, started in the 1960s with birth control education. The natural rate of population increase by the early 1970s had already fallen. From 1974 to 1982 the average rate of natural population growth was 3.8/1000. Reproduction has gone from a rising trend to a stabilized trend. The base of the population structure pyramid has shrunk; the number of youths aged from birth to 14 years has fallen from 35.05% in 1964 to 21.77% in 1982. The number of people who must be supported (the old and the young) has decreased, lessening society's responsibility for them. 29.45% of the total population are over 65 years or under 14. Society's coefficient factor of support has fallen from 66.31% in 1964 to 41.75%. There is a decrease in the number of people marrying at a young age; the trend is toward marriage at a later age. The average age at marriage had risen from 23.81 years in 1980 to 23.89 years in 1981. The fertility rate has decreased, as has the number of offspring per woman. 1 child family is on the rise and multiple children family is on the decline. In 1981 the 1 child rate reached 92.98%, the 2 children rate was 6.63% and the multiple children rate was 0.49%. Prior to 1979 the 1 child rate was under 10%. The fertility rate fell from 136/1000 in the 1960s to 41.5/1000 in 1981.     

Age distribution and the stable equivalent

Some populations, like that of the United States in the 1950's, have a smaller proportion of women of reproductive age than they would ultimately attain with continuance of their age-specific birth and deaths rates, a continuance which produces the condition known in demography as stability. Others, like that of the United States in the 1930's, have relatively more women of reproductive age than they would ultimately attain with stability. A way of studying ages is to calculate how many women of stable age distribution would be equivalent from the viewpoint of reproduction to the women observed. This stable equivalent was 69,535,000 or 16 percent below the observed United States female population in 1955, and 12 percent above the observed in 1935. The stable equivalent is a measure of fertility potential, closely related to R. A. Fisher's reproductive value. Calculations for four countries illustrate how a fall of the birth rate, for example in demographic transition, occasions an age distribution in which the stable equivalent is greater than the observed number of women. The notion of stable equivalent is useful for comparison because changes in it are nearly invariant with respect to the age-pattern of fertility used. The statement that the United States stable equivalent increased by 11 percent between 1960 and 1965 holds irrespective of whether the 1960 or the 1965 age-specific fertility and mortality rates are used as standard.     

Family planning achievements as suggested by changes of total fertility and party birth rate]

The dynamic characteristics of China's 5 distinct stages of population development since the People's Republic of China was established in 1949, namely, 1950-1958, 1959-1963, 1964-1970, 1971-1981, and 1982-present, are outlined and discussed. By tracing both the overall rate of population growth and age-specific fertility rates for women aged 15-45 (5-year groups), a clear pattern emerges which indicates that the rates of early and late fertility (ages groups 15-19 and 30-45) are significantly declining. This is interpreted as a key factor in the overall decline in fertility rate. Annual statistics showing the number of children per woman of childbearing age and interval between 1st marriage and 1st birth are compared and discussed. It is concluded that the overall decline in birth rate and fertility rate since the 1970's is attributable to China's successful family planning campaign.     

总和生育率影响因素实证研究

中国的计划政策三十多年的实施对控制人口数量起了积极的作用,也使中国人口结构和人口素质发生了巨大变化。本文通过对世界109个国家的经济、社会文化和其他数据共20项进行回归分析,建立了国家总和生育率的线形回归模型,并根据该模型估计出当前中国在无计划生育条件下的总和生育率。以此研究目前计划生育政策对我国总和生育率的影响,针对严峻的人口问题提出了相应政策建议。     

中国妇女生育水平变动考证和未来人口发展的策略选择

1990年以来各类人口调查和相关学者的研究结果显示,目前的低生育水平的实现有外在政策强力的作用,更有中国社会经济发展内生化的作用;真实的生育水平既不是调查包括人口普查所显示的那样低(低于1.5),也不是有关部门和政府所想象的那样高。调查显示农村居民平均生育意愿不会高于2个孩子,这是生育率持续稳定的根本。众所周知,为了保证人口稳定持续的发展,应使妇女生育率保持更替水平或至少接近更替水平。从人口发展规律和人口发展与社会经济发展相适应的规律出发,结合当前我国居民生育意愿和生育水平走低的实际,我们应该抓住生育政策调整的最佳时期,调整应该在最佳时期即未来5-10年内完成。