A preliminary analysis of negative population growth in Taicang County]

This report attempts to analyze the negative population growth and its significance in Tai-Cang County, China. Based on population data provided by local Tai-Cang authorities, family planning effectively lowered the birth rate from 11.9% between 1960-1969 to 3.0% between 1979-1983. The rate of single-child families grew enormously while the number of 2-child families reached a record low. Families with more than 2 children virtually vanished by 1983. Moreover, while a younger marriage age in 1981 and 1982 contributed to a slight increase in the birth rate, new marriage laws in 1983 caused an older marriage age and acted to lower the birth rate due to the fact that mothers were bearing children at an older age. A change in population components also influenced this low birth rate: the county population below the age of 14 is 21.2% compared with 33.6% nationally; however, the percentage of the population in this county over the age of 65 is 8.5% while the national figure is 4.9%. Finally, the marriagable population of females (i.e., 23 years old) was slightly lower between 1982-1984 due to the low birth rate seen from 1959-1961. The findings indicate that family planning is effective in lowering birth rates along with late marriages and older childbearing ages. The negative population growth in Tai-Cang County, however, is a temporary phenomenon. The indications are that the problems and shortcomings of family planning must be overcome, regional population planning must be improved, and the study of eugenics and optimum population reinforced. The report also notes that the population trend is toward aging.     

中国双生子出生性别比研究

人口自然出生性别比是分析和评价人口出生性别比偏离的重要指标,中国对人口自然出生性别比的研究一直比较缺乏。人的出生性别比正常范围为102～107,国内一般都是以其上限作为标准判断人口出生性别比偏高的程度。但是这种做法是值得商榷的。利用第四次全国人口普查资料中的双生子信息探讨双生子出生性别比特征。研究表明,中国1989年双生子出生性别比为104.87,在女性主要生育年龄阶段生育的双生子出生性别比是相当稳定的,比较接近自然状态下的出生性别比。相比较而言,中国人口出生性别比不仅普遍偏高,而且随女性生育年龄变化的模式也不相同。     

Understanding the sex ratio in India: A simulation approach

The highly masculine sex ratio in India has increased substantially in the twentieth century, in contrast to most other countries in the world. Competing arguments alternatively posit under-enumeration, highly masculine sex ratios at birth, or excess female mortality throughout the life course as the factors underlying the level of the overall sex ratio; these arguments have not been resolved. Based on population projections that simulate population dynamics, our findings show that small differences in mortality at young ages, persisting over a long period, as well as a sex ratio at birth of 106 males per 100 females, result in a highly masculine population sex ratio.     

90年代以来中国夫妇年龄差变动趋势及其原因分析

夫妇年龄差的研究是人口学研究的一个重要领域。但目前的研究由于数据来源多样化,得出的结论不尽一致,关于年龄差的变化方向也没有形成定论。为此,本文利用我国三期妇女地位调查数据,对年龄差变动趋势进行分析。结果发现：我国同龄婚配的特点非常稳定,其比例维持在16％～17％之间。中国夫妇年龄差模式自90年代以来,发生了较大的变化,2010年中国传统的＂男高女低＂的婚配模式有所改变,这种＂男高女低＂婚姻明显下降,而＂女高男低＂婚姻明显升高,扣除同龄婚后二者平分秋色。其原因可能与我国出生性别比持续偏高和婚姻观念的转变等因素有关。     

A new look at the marriage market and nuptiality rates, 1915–1958

The system of nuptiality probabilities for never married males and females, the “marriage regime,” is viewed as a population transformation, which operates on a population thereby changing the composition. The marriage regime has many properties common to other population transformations, but embodies a constraint such that, in general, the marriage regime cannot be strictly stable over time. The approach is applied to study the “marriage squeeze,” the alteration in marriage patterns that results from an imbalance in the “marriage market” or numbers of never married males and females at the usual marriage ages. Using data on age at first marriage for the 1960 American white population, nuptiality probabilities by single year of age and sex are estimated for the years 1915–58. Annual estimates also are made of the relative number of eligible mates (never married of the usual marriage ages) for never married persons of a given age and sex. No close correspondence is found between annual fluctuations in the marriage market and in the nuptiality probability, possibly because of the crudeness of the estimates. Alternatively, response to the imbalance may take another form such as marriage postponement or a redefinition of eligibility.     

Skewed Sex Ratios at Birth and Future Marriage Squeeze in China and India, 2005–2100

I examine the potential impact of the anticipated future marriage squeeze on nuptiality patterns in China and India during the twenty-first century. I use population projections from 2005 to 2100 based on three different scenarios for the sex ratio at birth (SRB). To counteract the limitations of cross-sectional methods commonly used to assess the severity of marriage squeezes, I use a two-sex cohort-based procedure to simulate marriage patterns over the twenty-first century based on the female dominance model. I also examine two more-flexible marriage functions to illustrate the potential impact of changes in marriage schedules as a response to the marriage squeeze. Longitudinal indicators of marriage squeeze indicate that the number of prospective grooms in both countries will exceed that of prospective brides by more 50% for three decades in the most favorable scenario. Rates of male bachelorhood will not peak before 2050, and the squeeze conditions will be felt several decades thereafter, even among cohorts unaffected by adverse SRB. If the SRB is allowed to return to normalcy by 2020, the proportion of men unmarried at age 50 is expected to rise to 15% in China by 2055 and to 10% in India by 2065. India suffers from the additional impact of a delayed fertility transition on its age structures.     

The Old Old — or the New Old?

This paper gives an account of the demographic trends that are bringing about changes in the population aged 80 years and older in Australia. The old old population of the future will differ in size and structure from earlier cohorts reaching advanced age: an examination is made of the contribution of the effects of past birth rates; recent changes in mortality at older ages; the impact of immigration especially on the cultural diversity of the old old; and changes in sex ratios and marriage patterns that result in changes in social circumstances. The indications are that a much more dynamic view of the old old is required. The present report is the first in a three-part study which mill cover social and health trends and discuss the implications of the newly emergent old old population for social policy.     

What’s happening to the age at first birth in the United States? A study of recent cohorts

This paper analyzes cross-cohort trends in the age pattern of women at first birth in the United States. The analysis involves fitting the Coale-McNeil marriage model to the age distribution of first birth frequencies for a number of recent white and nonwhite cohorts. Methodologically, the results (a) provide support for the application of the Coale-McNeil marriage model to first birth data, and (b) demonstrate the ability of the model to accurately project first birth fertility for cohorts which have yet to complete their childbearing years. Substantively the results indicate (a) that the proportion of women who will never have a first birth is increasing across cohorts and can be expected to be as high as .25 and .20 for recent white and nonwhite cohorts respectively; (b) that recent nonwhite cohorts have an appreciable number of first births at earlier ages than their white counterparts, as well as a lower mean age at first birth and increasingly less dispersion (across cohorts) in their age at first birth; and (c) that the mean age at first birth and the proportion of first births occurring between ages 25 and 34 is increasing across cohorts of white women but is stable across cohorts of nonwhite women.     

Does the marriage market sex ratio affect parental sex selection? Evidence from the Chinese census

Recent increases in the (male/female) sex ratio at birth in eastern Asia are thought to be associated with a preference for sons and to result from parental sex selection. However, males are less likely to marry and to have offspring as the ratio increases, and that decreases the expected number of grandchildren. Using data from the 2000 Chinese census, we test whether the sex ratio in the marriage market has an effect on the gender of subsequent births and hence on the sex ratio of the birth cohort. The slow population growth caused by the Great Famine in the early 1960s and the quick recovery that followed produced major changes in the sex ratio for those of marriageable age two decades later. We estimate that an increase of 1 % in the number of marriageable males relative to females, the marriage market sex ratio, would decrease the probability of having a son by 0.02 percentage points. That implies that the Great Famine, which occurred around 1960, led to an increase in the early 1980s of 5.8 extra male births per 100 females.     

Effect of Conflict on Age at Marriage and Age at First Birth in Rwanda

Using Rwanda Demographic and Health Survey 2005 data, we estimate a Cox proportional hazard model to identify the determinants of age at marriage and age at first birth and whether these decisions were affected by conflict. We find that women living in clusters accounting for a larger proportion of sibling deaths in 1994, the year of the genocide, were more likely to marry later and have children later compared with those living in clusters accounting for a lower proportion of sibling deaths. Women living in regions with higher levels of under-five mortality were more likely to have their first child earlier compared with women living in regions with lower infant mortality. The age at marriage was probably affected by two reasons: the change in age structure and sex ratio of the population following the genocide, and the breakdown of kinship in the case of women who lost their siblings.     

Modeling momentum in gradual demographic

The analysis of population momentum following a gradual decline in fertility to replacement level provides valuable insights into prospects for future population growth. Here, we extend recent work in the area by applying a new form of the quadratic hyperstable (QH) model, which relates exponentially changing fertility to the resultant exponentiated quadratic birth sequence. Modeling gradual transitions from an initial stable population to an ultimate stationary population indicates that such declines in fertility increase momentum by a product of two factors. The first factor is a previously noted continuation of stable growth for half the period of decline. The second is a not previously appreciated offsetting factor that reflects the interaction between the decline in fertility, the changing age pattern of fertility, and the changing age composition of the population. Numerical examples using both hypothetical and actual populations demonstrate that for declines of any length, the product of the two factors yields momentum values that closely agree with the results of population projections. The QH model can examine monotonic transitions between any two sets of constant vital rates. As a generalization of the fixed-rate stable model, it has great potential value in numerous areas of demographic analysis.     

Cycles in the two-sex problem: an investigation of a nonlinear demographic model

"A fundamental shortcoming of classic stable population theory is its failure to handle populations differentiated by sex. The classic theory is linear while the two-sex problem is inherently nonlinear. Previous two-sex investigations have focused on equilibrium conditions rather than dynamics, and ignored competition between age groups for marriage partners. This study makes a start at analyzing dynamics and models that incorporate competition, which can play an important role in any realistic marriage model and can turn a model with a stable equilibrium sex ratio into one with a cycling equilibrium." This is a revised version of a paper originally presented at the 1990 Annual Meeting of the Population Association of America. (SUMMARY IN FRE)     

How useful are the demographic surveys in explaining the determinants of early marriage of girls in the Terai of Nepal?

In recent decades significant changes in Nepalese society have greatly contributed to the increase in age at marriage of girls in Nepal. Factors responsible for these changes include educational development, urbanization and development of mass communications. However, many parents still marry their daughters at very young ages and this practice is particularly prevalent in the Terai region. This paper examines several demographic data sets with a view to assessing their utility for understanding the determinants of early age of marriage of girls in the Terai. The Nepal Family Health Survey (1996), Nepal Demographic and Health Surveys (2001, 2006), the Nepal Adolescents and Young Adults Survey (1999) and the 2001 Population Census of Nepal describe changes in at marriage over time. Factors such as sex, religion, education, geographic region, place of residence (rural/urban), economic status of the household and of women, and occupation are included in these data sets. However, other factors such as age at menarche, dowry and cost of marriage and cross-border marriage migration, which have been found to affect the prevalence of the lower age at marriage of girls in the Terai region, have not been included in the existing demographic surveys. Findings from the current study suggest that these variables should be included in future demographic surveys.     

In Living Memory: The Demographic Dynamics of Event Recollection in a Stable Population*

We model a stable population that has experienced an important historical event and the declining proportion, as time passes, of the population that remembers that event. The proportion is determined by the demographic characteristics of the population, including its age distribution, the natural rate of growth, the underlying birth rate, the life table probabilities to which the population is subject, and the effects of immigration and emigration under alternative assumptions about the nature of the event. (We distinguish between “local” and “universal” events.) It is determined also by the choice of an age of awareness of children at the time the event occurred. We preface development of the model by noting examples of major events of the kind we have in mind and, after development, explore the model's sensitivity to different parameter specifications by experimental simulation. The output of each experiment is a sequence of “remembering” proportions at successive decade intervals and the corresponding mean ages of the “rememberers” in relation to the overall mean age of the population.     

The relationship of the crude birth rate and its components to social and economic development

Using well-known techniques of regression analysis, we decompose the crude birth rate into six analytical components, indicating illegitimacy, the marriage rate, legitimate fertility, and sex and age composition. All the components except sex structure are important in determining differences in crude birth rates across countries of the world. The model is elaborated by showing how economic development affects the crude birth rate through its basic demographic components.     

Trends in age at marriage in postwar Ireland

Age at marriage in the Republic of Ireland has declined substantially from the very high level that prevailed in 1946. Between 1946 and 1969 the median age of grooms fell from 32 to 26 and of brides from 27 to 24. To some extent this is a reflection of the declining importance of the rural population but to a much greater extent it is due to the falling age at marriage among all sections of the population. Simultaneous with the decline in age at marriage, the frequency distributions of brides' and grooms' ages have become both more skewed and more peaked. Thus earlier marriage has also meant greater uniformity in age at marriage, but the phenomenon of first marriage at a fairly advanced age persists. There has been a marked trend towards greater equality between husbands' and wives' ages over the postwar period: the proportion of marriages in which there was less than five years' gap between the ages of the bride and groom rose from 49 percent in 1946 to 71 percent in 1969. The percentage of marriages in which the groom was ten or more years older than the bride has fallen from 22 to seven percent. The evidence suggests that the “marriage market” became less favourable to males (especially older males) over the period and that part of the narrowing in the gap in relative age of brides and grooms has been due to the greater willingness of younger males to marry. It also seems that changes in the age structure of the unmarried population has had an impact on the age distribution of grooms.     

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.     

Demographic Consequences of Gender Discrimination in China: Simulation Analysis of Policy Options

The large number of missing females in China, a consequence of gender discrimination, is having and will continue to have a profound effect on the country’s population development. In this paper, we analyze the causes of this gender discrimination in terms of institutions, culture and, economy, and suggest public policies that might help eliminate gender discrimination. Using a population simulation model, we study the effect of public policies on the sex ratio at birth and excess female child mortality, and the effect of gender discrimination on China’s population development. We find that gender discrimination will decrease China’s population size, number of births, and working age population, accelerate population aging and exacerbate the male marriage squeeze. These results provide theoretical support for suggesting that the government enact and implement public policies aimed at eliminating gender discrimination.     

流动人口的生育意愿与生育行为差异研究

文章利用中国人民大学人口与发展研究中心于2009年在北京朝阳区、广东东莞市和浙江诸暨市组织进行的流动人口调查数据,分析了流动人口的生育意愿与生育行为之间的关系。研究发现,流动人口中既存在生育意愿与生育行为悖离的一面又有一致的一面,在4个维度上均有所表现,在时间、间隔和性别上二者更多的表现为悖离,在数量上更多的表现为一致。研究还发现,年龄、初婚年龄、初育年龄、受教育程度、职业角色、已有孩子的性别结构等对生育意愿与生育行为的悖离有显著影响。     

中国30年早婚变化分析--基于“六普”数据

文章使用第六次全国人口普查数据对1980年以来的早婚率进行了分析,发现30年来早婚率经历了从急剧升高到逐渐下降又到部分省份升高的过程,早婚率由女性高于男性转变为男性高于女性;总体上农村地区的早婚率高于城镇,受教育程度越低的群体中早婚发生率越高,当前男性早婚现象更多发生在部分东中部地区和西部地区,女性早婚现象更多发生在西部地区。进一步分析认为,导致早婚的根源是民间传统习俗在部分人群受教育程度低、性别比失衡、青少年性意识萌动但性教育滞后以及基层服务缺位和基层管理弱化等因素作用下的结果。