Children as insurance

This paper presents a dynamic model of fertility decisions in which children serve as an incomplete insurance good. The model incorporates uncertainty about future income and the survival of children as well as a discrete representation of the number of children. It contributes to the understanding of the negative relation between fertility and education, shows why parents may demand children even if the return is negative, and explains why fertility might rise with increasing income when income is low and decrease when income is high. Furthermore, the model can account for the decline in fertility when the risk of infant and child mortality decreases. Finally, the implications for empirical tests of the demand for children are also examined. Received: 8 September 1998/Accepted: 9 June 1999     

Choosing the choice: Reflections on modelling decisions and behaviour in demographic agent-based models

This paper investigates the issues associated with choosing appropriate models of choice for demographic agent-based models. In particular, we discuss the importance of context, time preference, and dealing with uncertainty in decision modelling, as well as the heterogeneity between agents in their decision-making strategies. The paper concludes by advocating empirically driven, modular, and multi-model approaches to designing simulations of human decision-making, given the lack of an agreed strategy for dealing with any of these issues. Furthermore, we suggest that an iterative process of data collection and simulation experiments, with the latter informing future empirical data collection, should form the basis of such an endeavour. The discussion is illustrated with reference to selected demographic agent-based models, with a focus on migration.     

Risk, uncertainty and family formation: The social context of poverty groups

Abstract Despite the assumptions of many demographers that the net returns from children for non-elite groups in underdeveloped areas are likely to be negative, high fertility persists in most of these societies. Both cultural and institutional explanations have been proposed to account for this. We attempt to provide some mediation between these competing models, by introducing the elements of risk and uncertainty as factors likely to induce poverty and lead works to opt for the 'high fertility, low quality' pattern of investment of time and money in family formation. Drawing upon the work of Wharton in subsistence agriculture practices, several alternative decision-making models are proposed to account for both the persistence of high fertility, and the declines that have been registered in selected areas, such as Taiwan and perhaps China. The empirical work of Mueller on Taiwanese expectations of returns on children and the concomitant variation in family-size preferences is consistent with the models proposed. Some implications for uncertainty and risk-reduction strategies in family planning and other social welfare programmes are drawn.     

Does son preference influence children's growth in height? A comparative study of Chinese and Filipino children

Research has demonstrated that son preference has a serious impact on the survival and well-being of female infants and children in some parts of South and East Asia, but little is known about the consequences of son preference in later childhood and adolescence. We compare children's growth trajectories in height over childhood and adolescence in China, where the level of son preference is relatively high, and the Philippines, where it is relatively low. Children's height reflects long-term nutritional status and exposure to infectious diseases, both influenced by household decision-making and, presumably, by a preference for sons. Using data from two high-quality longitudinal studies and multilevel growth models, we find that male children in China show an additional height advantage relative to their female counterparts, when compared to the sex difference in growth trajectories in the Philippines. Further analysis reveals that the additional advantage of males in China is stronger in rural areas.     

The mechanisms mediating the effects of poverty on children’s intellectual development

Although adverse consequences of poverty for children are documented widely, little is understood about the mechanisms through which the effects of poverty disadvantage young children. In this analysis we investigate multiple mechanisms through which poverty affects a child's intellectual development. Using data from the NLSY and structural equation models, we have constructed five latent factors (cognitive stimulation, parenting style, physical environment, child's ill health at birth, and ill health in childhood) and have allowed these factors, along with child care, to mediate the effects of poverty and other exogenous variables. We produce two main findings. First, the influence of family poverty on children's intellectual development is mediated completely by the intervening mechanisms measured by our latent factors. Second, our analysis points to cognitive stimulation in the home, and (to a lesser extent) to parenting style, physical environment of the home, and poor child health at birth, as mediating factors that are affected by lack of income and that influence children's intellectual development.     

Individual Uncertainty About Longevity

This article presents an assessment of individual uncertainty about longevity. A survey performed on 3,331 French people enables us to record several survival probabilities per individual. On this basis, we compute subjective life expectancies (SLE) and subjective uncertainty regarding longevity (SUL), the standard deviation of each individual’s subjective distribution of her or his own longevity. It is large and equal to more than 10 years for men and women. Its magnitude is comparable to the variability of longevity observed in life tables for individuals under 60, but it is smaller for those older than 60, which suggests use of private information by older respondents. Our econometric analysis confirms that individuals use private information—mainly their parents’ survival and longevity—to adjust their level of uncertainty. Finally, we find that SUL has a sizable impact, in addition to SLE, on risky behaviors: more uncertainty on longevity significantly decreases the probability of unhealthy lifestyles. Given that individual uncertainty about longevity affects prevention behavior, retirement decisions, and demand for long-term care insurance, these results have important implications for public policy concerning health care and retirement.     

Regression-like analysis of birth interval sequences

Employing a family of generalized linear models for the gamma distribution, the structure of birth interval data derived from three historical populations is examined. The relative importance of such factors as current age, parity of the mother, and duration of marriage in determining the length of succeeding intervals is investigated. The results suggest that the three data sets have a common, rather simple structure and various applications of such empirical models are considered.     

Social networks and HIV/AIDS risk perceptions

Understanding the determinants of individuals' perceptions of their risk of becoming infected with HIV and their perceptions of acceptable strategies of prevention is an essential step toward curtailing the spread of this disease. We focus in this article on learning and decision-making about AIDS in the context of high uncertainty about the disease and appropriate behavioral responses. We argue that social interactions are important for both. Using longitudinal survey data from rural Kenya and Malawi, we test this hypothesis. We investigate whether social interactions--and especially the extent to which social network partners perceive themselves to be at risk--exert causal influences on respondents' risk perceptions and on one approach to prevention, spousal communication about the threat of AIDS to the couple and their children. The study explicitly allows for the possibility that important characteristics, such as unobserved preferences or community characteristics, determine not only the outcomes of interest but also the size and composition of networks. The most important empirical result is that social networks have significant and substantial effects on risk perceptions and the adoption of new behaviors even after we control for unobserved factors.     

Age,period, and cohort effects in demography: a review

This paper considers only the vital events of demographic measurement, the factors influencing the rate at which those events occur and then investigates the consequences of patterns of these events. It reviews the state of the art of age, period and cohort analysis for demographic dependent variables. Major examples of such analyses are given in both mortality and fertility studies. In the area of mortality the conventional approach to such analysis apears to be well suited to a wide range of applications yielding useful results. The reasons for this suitability are: early childhood experience is important in many major disease and death processes, so that cohorts are legitimately viewed as acquiring early on a certain fixed susceptibility; data sometimes stretch back far enough that stationary standards of age patterns can be developed empirically, and applied to later experience; and, logarithmic or logistic transformations linearize comparisons of age schedules or mortality so that standard statistical procedures are suitable. Applications of age, period, and cohort analysis are not always routine; external constraints are required, in the form of theoretically based and mathematically expressed age patterns of mortality, in order to distinguish effectively between period and cohort effects. A set of models of age patterns of mortality that are based on cohort as well as period experience could be constructed with useful applications. With fertility analysis the conventional approach is much less suitable. Once goal directed behavior is introduced, empirical examinations must be based on theories or assumptions about how such goals are formulated and pursued. Conventional analysis might suffice only if one is prepared to accept the assumption that all pertinent goals and strategies are formulated before the initiation of childbearing and remain unaffected by subsequent events. This assumption is untenable for modern developed populations and the forms of analysis appropriate to age period cohort investigations of fertility will have to develop along with theories of reproductive behavior.     

母亲受教育水平对儿童健康的影响及其路径

母亲的受教育水平对儿童的健康发展具有重要影响,但鲜有研究针对其影响路径进行深入分析。本文基于1991-2015年中国营养与健康调查数据,利用母亲的兄弟姐妹个数作为母亲受教育水平的工具变量,采用两阶段最小二乘法(2SLS),探讨了母亲受教育水平对儿童健康的影响及其路径。研究表明,母亲受教育水平每提高1年,儿童的年龄别身高Z评分和年龄别体重Z评分分别平均显著提高0.129和0.14个标准差,具体来说,5岁儿童身高和体重对应是提高约0.6厘米和0.3千克。使用九年义务教育的实施作为母亲受教育水平的工具变量时,结果仍然稳健。影响路径的研究结果说明,母亲的受教育水平可通过提高其膳食知识水平和家庭资产指数来影响其儿童的健康发展。进一步的异质性分析发现,农村母亲受教育水平对家庭资产指数和儿童健康的影响显著大于城市,但对膳食知识水平的影响不存在城乡差异。基于以上分析,提高女性的教育投入,尤其是农村女性的教育投入可以显著改善儿童的健康状况。     

The effect of marital disruption on children’s health

This study uses retrospective illness histories to investigate whether children's health deteriorates after parental separation. Separation is associated with illness in a multivariate cross-sectional analysis as well as in an analysis of a sample of disrupted children only, in which illness rates before and after separation are compared. Three explanations are hypothesized: (1) divorce reduces the resources available to children, (2) the stress of divorce depletes children's health, and (3) frailer children are selected into divorce. The first hypothesis has stronger support than the second, but the data are too poor for a rigorous test of either. The selection hypothesis is not supported.     

Comparison of household-survey estimates with projections of mortality and orphan numbers in sub-Saharan Africa in the era of HIV/AIDS

The United Nations publishes estimates of HIV prevalence, AIDS mortality, and orphan numbers for all countries of the world. It is important to assess the validity of these model-based estimates since they underpin much policy concerned with care and prevention. Household surveys that ask questions about the survival of children's parents (orphanhood) offer an independent source of data with which these estimates can be compared. Survey estimates of maternal and paternal orphans are significantly lower than model estimates for 40 surveys in 36 countries of sub-Saharan Africa (p < 0.001, p = 0.002). This is probably because adult mortality from causes other than AIDS is lower than assumed in the models, although under-reporting of orphanhood in surveys may also play a role. Reducing adult mortality from causes other than AIDS brings the model estimates into close agreement with the surveys. This suggests that the fraction of orphans attributable to AIDS is greater than estimated previously.     

Data on survival of recent births as a source of child mortality estimates in the developing world: An assessment of census data

In many less developed countries, household surveys collect full and summary birth histories to provide estimates of child mortality. However, full birth histories are expensive to collect and cannot provide precise estimates for small areas, and summary birth histories only provide past child mortality trends. A simple method that provides estimates for the most recent past uses questions about the survival of recent births in censuses or large household surveys. This study examines such data collected by 45 censuses and shows that on average they tend to underestimate under-5 mortality in comparison with alternative estimates, albeit with wide variations. In addition, the high non-sampling uncertainty in this approach precludes its use in providing robust estimates of child mortality at the country level. Given these findings, we suggest that questions about the survival of recent births to collect data on child mortality not be included in census questionnaires.     

Social Construction of Public Intellectuals in Vietnam: Current Situation and Possible Changes

In the literature on political support, much empirical effort has been devoted to the link between economic performance and satisfaction with democracy. Nevertheless, analyses are often inconclusive in their findings. This study tries to renew the interest in the topic by using multilevel models to analyse 108 surveys from the repeated cross-sectional Eurobarometer data between 1985 and 2013, and focuses on southern European countries which share political and economic characteristics. Thus, the article links economic trends to changes in satisfaction with democracy in Greece, Italy, Portugal and Spain, also emphasizing the relevance of transformations in their political systems. The results demonstrate that low economic performance seems to negatively affect citizens’ satisfaction with democracy in the four countries and across the whole period analysed. This also holds true for different model specifications and when other potential factors such as the format and the performance of the institutional context are controlled for. By providing empirical evidence based on a longitudinal analysis, this article contributes to the wider debate on how economic conditions influence opinions about democracy.     

Research Note: What Counts as a House? Comparing 2010 Census Counts and Administrative Records

As a tool for fulfilling data needs for small area (subcounty) analysis, demographers are increasingly turning to administrative records such as building permits and tax assessor records as a source of data for use in producing small area demographic estimates. While Census counts are considered to be the “gold standard,” administrative records provide a fine level of spatial detail and a valuable source of information for intercensal years. However, there is uncertainty about the quality of administrative records data for use in estimation. This analysis builds upon earlier research by comparing administrative records-based housing unit estimates developed during the 2000s decade with housing counts from the 2010 Census in San Diego County. Results show that both administrative records and Census counts have strengths and weaknesses that should be understood by the data user.     

Empirical Prediction Intervals for County Population Forecasts

Population forecasts entail a significant amount of uncertainty, especially for long-range horizons and for places with small or rapidly changing populations. This uncertainty can be dealt with by presenting a range of projections or by developing statistical prediction intervals. The latter can be based on models that incorporate the stochastic nature of the forecasting process, on empirical analyses of past forecast errors, or on a combination of the two. In this article, we develop and test prediction intervals based on empirical analyses of past forecast errors for counties in the United States. Using decennial census data from 1900 to 2000, we apply trend extrapolation techniques to develop a set of county population forecasts; calculate forecast errors by comparing forecasts to subsequent census counts; and use the distribution of errors to construct empirical prediction intervals. We find that empirically-based prediction intervals provide reasonably accurate predictions of the precision of population forecasts, but provide little guidance regarding their tendency to be too high or too low. We believe the construction of empirically-based prediction intervals will help users of small-area population forecasts measure and evaluate the uncertainty inherent in population forecasts and plan more effectively for the future.     

The development and use of demographic models

In this review, we first examine two classical demographic models - conventional life tables and stable populations - and a modern generalization of stable population theory; we then discuss mathematical models of conception and birth. These models involve purely mathematical relations in formal demography as opposed to empirical regularities. Next we consider model age schedules of mortality, nuptialitiy, marital fertility, fertility, and migration that are explicitly based on such empirical patterns. We close this empirical section with a discussion of model stable populations, which are based on model life tables. We next examine the use of demographic models in forecasting future mortality, nuptiality, and fertility and in population projection. Following a discussion of microsimulation models, which gives us the opportunity to mention model age schedules of post partum amenorrhoea and of sterility, we close with observations about the purposes and uses of demographic models.     

家庭教育支出决定因素分析--来自中国城镇住户调查数据的经验证据

利用北京、辽宁、浙江、广东、四川与陕西2002年和2009年的城镇住户调查数据对家庭教育支出行为的决定因素和家庭教育支出的影响机制进行了实证检验与扩展分析。结论表明；（1）2002年家庭教育总支出的收入弹性大于2009年的家庭教育总支出收入弹性，且2002年的收入弹性大于1；家庭教育支出行为与户主年龄呈现显著的“U”型关系，且女孩比男孩获得更多的家庭教育资源；（2）各分项教育支出中，培训费支出受家庭可支配收入的影响最大；（3）城市人口规模与家庭教育支出之间呈现正相关关系；（4）总体而言，妻子对家庭教育支出的影响显著大于丈夫的影响，这主要体现在受教育年限方面。     

人口规模、结构对区域碳排放的影响研究——基于中国省级面板数据的经验分析

目前关于人口对碳排放影响的经验研究,得出大相径庭的结论。基于这种背景,本文以STIRPAT模型为研究起点,运用中国1997～2009年30个省份的面板数据,采用Driscoll和Kraay基于固定效应中纠正异方差、序列相关和截面相关的估计方法,具体考察了地区人口规模、结构对碳排放量的影响。研究表明,在考虑人口结构因素的情况下,人口规模的排放弹性显著为1,因此,以中国为样本研究碳库兹涅茨曲线(CKC)并不会产生太大偏误。在反映人口结构的变量中,劳动年龄人口对碳排放有显著的正向影响,家庭户规模有显著负向影响,而城镇化率对于碳排放的影响并不显著。     

Life course transitions of American children: Parental cohabitation, marriage, and single motherhood

We examine the life course transitions into and from families headed by unmarried cohabiting couples for a recent cohort of American children. Life table estimates, based on data from the National Longitudinal Survey of Youth mother-child files, indicate about one in four children will live in a family headed by a cohabiting couple sometime during childhood. Economic uncertainty is an important factor determining whether children in single-parent families subsequently share a residence with a mother's unmarried partner. Moreover, virtually all children in cohabiting-couple families will experience rapid subsequent changes in family status. Our estimates provide a point of departure for future work on children's exposure to parental cohabitation and its social and economic implications.