首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
"We present a mortality model where nationally representative survey data on risk factor distributions are combined with data on cohort mortality rates to increase information, i.e., a fixed marginal risk factor distribution is combined with a cohort model representing unobserved individual risk heterogeneity. The model is applied to lung cancer mortality in nine U.S. white male cohorts aged 30 to 70 in 1950 and followed 38 years. Estimates of the cohort specific proportions of smokers were made from the National Health Interview Survey. Comparisons are made for models with different patterns of changes with age of individual heterogeneity." (SUMMARY IN FRE)  相似文献   

2.
The consequences of unobserved heterogeneity in a sequential logit model   总被引:1,自引:0,他引:1  
Cameron and Heckman (1998) established that a sequential logit model is more sensitive than many other models to the possible biasing influence of unobserved heterogeneity. This article proposes a method which allows researchers to find out how large this potential problem is for their data, their model, and their hypothesis of interest. This is done by proposing a set of scenarios for this unobserved heterogeneity, and showing how to estimate the effects of interest given these scenarios. The set of results from these scenarios give an indication of how sensitive the results are to assumptions regarding unobserved heterogeneity. This sensitivity analysis has been applied to a study of educational attainment in the Netherlands, and it showed that that the finding that the effect of father's education declined over transitions is quite sensitive to the assumptions made about unobserved heterogeneity, but that the finding that the effect of father's education declined over birth cohorts is more robust than is often feared.  相似文献   

3.

In analyzing mortality data there may be available information from survey and other sources that describe the marginal distribution of risk factors. We present a mortality model where nationally representative survey data on risk factor distributions are combined with data on cohort mortality rates to increase information, i.e., a fixed marginal risk factor distribution is combined with a cohort model representing unobserved individual risk heterogeneity. The model is applied to lung cancer mortality in nine U.S. white male cohorts aged 30 to 70 in 1950 and followed 38 years. Estimates of the cohort specific proportions of smokers were made from the National Health Interview Survey. Comparisons are made for models with different patterns of changes with age of individual heterogeneity.  相似文献   

4.
中国老年人的居住方式与其婚姻状况的关系分析   总被引:1,自引:0,他引:1  
焦开山 《人口学刊》2013,35(1):78-86
基于追踪调查数据,运用随机效应Probit模型分析老年人的居住方式与其婚姻状况的关系及其在不同性别和不同年龄段上的差异。研究发现,丧偶对老年人的居住方式存在显著影响,老年人在丧偶后更可能与子女同住。然而,在控制配偶照顾因素后,丧偶对老年人居住方式的影响却大幅下降。从性别和年龄上来看,丧偶对女性老年人居住方式的影响大于男性老年人,对高龄老年人的影响大于低龄老年人。同时,研究还发现,在控制人口特征、社会经济以及健康状况变量之后,未观测到的个体异质性对老年人居住方式存在显著影响。  相似文献   

5.
Measures of children’s time use, particularly with parents and siblings, are used to evaluate three hypotheses in relation to the vocabulary and mathematical skills development: (1) the resource dilution hypothesis, which argues that parental and household resources are diluted in larger families; (2) the confluence hypothesis, which suggests that the intellectual milieu of families is lowered with additional children; and (3) the admixture (“no effect”) hypothesis, which suggests that the negative relationship between family size and achievement is an artifact of cross-sectional research resulting from unobserved heterogeneity. Each hypothesis is tested using within-child estimates of change in cognitive scores over time with the addition of new children to families.  相似文献   

6.
In many countries educational branching points consist of more than two qualitatively different alternatives, and only some alternatives provide the opportunity of continuing into higher education. I develop a multinomial transition model for modeling the effects of family background characteristics and individual characteristics on these complex educational careers. The model controls for unobserved heterogeneity that may, if ignored, result in biased estimates. Compared to previous research, I explicitly include instrumental variables that ensure identification of the unobserved component. I apply the model to the Danish case and analyze data which covers the educational careers of a cohort of Danes born around 1954. I find that the model brings forward non-trivial heterogeneity in the influence of family background and ability on qualitatively different choice alternatives both within and across transitions. I also find that not controlling for unobserved heterogeneity leads to marked underestimation of the family background effect on both early and late transitions in the educational career.  相似文献   

7.
The rural-urban gap in infant mortality rates is explained by using a new decomposition method that permits identification of the contribution of unobserved heterogeneity at the household and the community level. Using Demographic and Health Survey data for six Francophone countries in Central and West sub-Saharan Africa, we find that differences in the distributions of factors that determine mortality-not differences in their effects-explain almost the entire gap. Higher infant mortality rates in rural areas mainly derive from the rural disadvantage in household characteristics, both observed and unobserved, which explain two-thirds of the gap. Among the observed characteristics, environmental factors-a safe source of drinking water, electricity, and quality of housing materials-are the most important contributors. Community characteristics explain less than onequarter of the gap, with about two-thirds of this coming from community unobserved heterogeneity and one-third from the existence of a health facility within the community. The effect of disadvantageous environmental conditions-such as limited electricity and water supply-derives both from a lack of community-level infrastructure and from the inability of some households to exploit it when available. Policy needs to operate at both the community and household levels to correct such deficiencies.  相似文献   

8.
This research determines whether the observed decline in infant mortality with socioeconomic level, operationalized as maternal education (dichotomized as college or more, versus high school or less), is due to its “indirect” effect (operating through birth weight) and/or to its “direct” effect (independent of birth weight). The data used are the 2001 U.S. national African American, Mexican American, and European American birth cohorts by sex. The analysis explores the birth outcomes of infants undergoing normal and compromised fetal development separately by using covariate density defined mixture of logistic regressions (CDDmlr). Among normal births, mean birth weight increases significantly (by 27–108 g) with higher maternal education. Mortality declines significantly (by a factor of 0.40–0.96) through the direct effect of education. The indirect effect of education among normal births is small but significant in three cohorts. Furthermore, the indirect effect of maternal education tends to increase mortality despite improved birth weight. Among compromised births, education has small and inconsistent effects on birth weight and infant mortality. Overall, our results are consistent with the view that the decrease in infant death by socioeconomic level is not mediated by improved birth weight. Interventions targeting birth weight may not result in lower infant mortality.  相似文献   

9.
This paper provides strong evidence that adult mortality has a negative impact on children educational outcomes, both over the short and the long run, in rural Madagascar. The underlying longitudinal data and the difference-in-differences strategy used overcome most of the previous cross-sectional study limitations, such as failure to control for child and household pre-death characteristics and unobserved heterogeneity. This paper also pays special attention to the heterogeneity, robustness, and long-run persistence of effects. Results show that orphans are on average 10 pp less likely to attend school than their nonorphaned counterparts, this effect being even more pronounced for girls and young children from poorer households. Results on adults further show that those orphaned during childhood eventually completed less education. These findings suggest that not only do households suffering unexpected shocks resort to schooling adjustments as an immediate risk-coping strategy, but also that adversity has long-lasting effects on human capital accumulation.  相似文献   

10.
In this study, we argue that the long arm of childhood that determines adult mortality should be thought of as comprising an observed part and its unobserved counterpart, reflecting the observed socioeconomic position of individuals and their parents and unobserved factors shared within a family. Our estimates of the observed and unobserved parts of the long arm of childhood are based on family-level variance in a survival analytic regression model, using siblings nested within families as the units of analysis. The study uses a sample of Finnish siblings born between 1936 and 1950 obtained from Finnish census data. Individuals are followed from ages 35 to 72. To explain familial influence on mortality, we use demographic background factors, the socioeconomic position of the parents, and the individuals’ own socioeconomic position at age 35 as predictors of all-cause and cause-specific mortality. The observed part—demographic and socioeconomic factors, including region; number of siblings; native language; parents’ education and occupation; and individuals’ income, occupation, tenancy status, and education—accounts for between 10 % and 25 % of the total familial influence on mortality. The larger part of the influence of the family on mortality is not explained by observed individual and parental socioeconomic position or demographic background and thus remains an unobserved component of the arm of childhood. This component highlights the need to investigate the influence of childhood circumstances on adult mortality in a comprehensive framework, including demographic, social, behavioral, and genetic information from the family of origin.  相似文献   

11.
The possible negative consequences of current low fertility levels are causing increasing concern, particularly in countries where the total fertility rate is below 1.5. Social inertia and self‐reinforcing processes may make it difficult to return to higher levels once fertility has been very low for some time, creating a possible “low‐fertility trap.” Policies explicitly addressing the fertility‐depressing effect of increases in the mean age at child‐bearing (the tempo effect) may be a way to raise period fertility to somewhat higher levels and help escape the “low‐fertility trap” before it closes. Reforms in the school system may affect the timing of childbearing by lowering the age at completion of education. A more efficient school system, which provides the same qualifications with a younger school‐leaving age, is potentially capable of increasing period fertility and hence exerting a rejuvenating effect on the age composition, even if the levels of cohort fertility remain unchanged. Such policies may also have a positive effect on completed cohort fertility.  相似文献   

12.
Amy Hsin  Christina Felfe 《Demography》2014,51(5):1867-1894
This study tests the two assumptions underlying popularly held notions that maternal employment negatively affects children because it reduces time spent with parents: (1) that maternal employment reduces children’s time with parents, and (2) that time with parents affects child outcomes. We analyze children’s time-diary data from the Child Development Supplement of the Panel Study of Income Dynamics and use child fixed-effects and IV estimations to account for unobserved heterogeneity. We find that working mothers trade quantity of time for better “quality” of time. On average, maternal work has no effect on time in activities that positively influence children’s development, but it reduces time in types of activities that may be detrimental to children’s development. Stratification by mothers’ education reveals that although all children, regardless of mother’s education, benefit from spending educational and structured time with their mothers, mothers who are high school graduates have the greatest difficulty balancing work and childcare. We find some evidence that fathers compensate for maternal employment by increasing types of activities that can foster child development as well as types of activities that may be detrimental. Overall, we find that the effects of maternal employment are ambiguous because (1) employment does not necessarily reduce children’s time with parents, and (2) not all types of parental time benefit child development.  相似文献   

13.
This article presents and analyzes findings from interviews with women aged 45–65; popular magazines targeting women in this age category, and popular books and blogs on a Swedish age-sensitive concept, tant. The term can be used in many different senses, ranging from polite to derogatory, connoting “aunt,” or “granny,” but also “little old lady” and “biddy”; the term tantig translating to “frumpish.” The article discusses different representations of tant, how she is used as a symbol of invisibility and no longer being seen as a sexual being, but outdated. The concept is used as a warning, indicating an unwanted way to grow old, when addressing middle-aged and older women. As of recently, tant has come to be celebrated by young women, praised for moral courage, for thrift and being represented as free from the male gaze, no longer aiming to please or fretting about appearances. The article sheds light on the different uses of the concept, where who is categorizing whom is of utmost importance. The tant is used as a symbol for doing age either by derogation or by celebration.  相似文献   

14.
Hill Kulu 《Demography》2014,51(3):881-893
Previous studies have shown that the risk of divorce is low during the first months of marriage; it then increases, reaches a maximum, and thereafter begins to decline. Some researchers consider this pattern consistent with the notion of a “seven-year itch,” while others argue that the rising-falling pattern of divorce risk is a consequence of misspecification of longitudinal models because of omitted covariates or unobserved heterogeneity. The aim of this study is to investigate the causes of the rising-falling pattern of divorce risk. Using register data from Finland and applying multilevel hazard models, the analysis supports the rising-falling pattern of divorce by marriage duration: the risk of marital dissolution increases, reaches its peak, and then gradually declines. This pattern persists when I control for the sociodemographic characteristics of women and their partners. The inclusion of unobserved heterogeneity in the model leads to some changes in the shape of the baseline risk; however, the rising-falling pattern of the divorce risk persists.  相似文献   

15.
Peng  Chenhong  Fang  Lue  Wang  Julia Shu-Huah  Law  Yik Wa  Zhang  Yi  Yip  Paul S. F. 《Social indicators research》2019,144(1):219-250

This study aims to investigate into the determinants of poverty in Hong Kong. Previous research on poverty, which usually adopted a logistic regression model to examine individuals’ probabilities of being poor, could not adequately reveal the heterogeneity in experiences among people across the poverty spectrum, therefore has limited policy effort to address diverse needs of individuals struggling with poverty. In the present study, this concern is addressed by using a quantile regression model to examine the differential effects of the determinants of poverty across the poverty spectrum. Data were drawn from the Hong Kong Panel Survey for Poverty Alleviation (n?=?1668). Logistic regression indicated that being elderly, being female, not having a partner, from a single-parent household, not being employed, living in public rental housing, have lower educational attainment, and have poor self-rated health, increased the probability of being poor. Informational support was a protective factor of poverty, while several negative life events, such as having family member(s) with disabilities/chronic diseases and having financial burden, were risk factors of poverty. Quantile regression analysis was adopted to further examine the extent to which determinants of poverty unfold across poverty spectrum, which was captured by five groups of “extremely poor”, “deeply poor”, “at the poverty line”, “near poverty” and “marginally poor”. Quantile regression indicated that people living across the poverty spectrum were similarly affected by not having a partner, living in single-parent households and not working. However, extremely poor and deeply poor were more adversely affected by old age than those near poverty and marginally poor. It is also discovered that public rental housing buffered the poverty risks more in those who lived in deep poverty than those who were near poverty and marginally poor. University education protected the near poverty and marginally poor to a larger extent than those who were extremely poor and deeply poor. Information support also buffered the poverty risks, and people living across the poverty spectrum were equally benefited from it.

  相似文献   

16.
In developed countries, mortality decline is decelerating at younger ages and accelerating at old ages, a phenomenon we call “rotation.” We expect that this rotation will also occur in developing countries as they attain high life expectancies. But the rotation is subtle and has proved difficult to handle in mortality models that include all age groups. Without taking it into account, however, long-term mortality projections will produce questionable results. We simplify the problem by focusing on the relative magnitude of death rates at two ages (0 and 15–19) while making assumptions about changes in rates of decline at other ages. We extend the Lee-Carter method to incorporate this subtle rotation in projection. We suggest that the extended Lee-Carter method could provide plausible projections of the age pattern of mortality for populations, including those that currently have very high life expectancies. Detailed examples are given using data from Japan and the United States.  相似文献   

17.
18.
将人口增长“稀释效应”嵌入一个四部门水平创新框架,提出一个同时内生化个体经济行为、R&D技术进步与人力资本积累的内生增长模型,推导并刻画了经济收敛于BGP均衡及影响经济增长率的因素,为解释人口增长对经济增长产生不确定影响的“正负符号之争”提供了微观基础分析。边际贡献在于:修正设定知识积累存在非规模效应且人力资本积累存在“稀释效应”,放宽对参数的上限或正负进行先验设定。得出结论:人口增长产生负向“稀释效应”与正向“思想效应”是影响经济增长的微观传导路径,正负效应共同作用门槛值大小的不同决定人口增长与经济增长呈非单调异质性不确定影响,进一步分析了稀释效应与门槛值之间的内在关联,数值模拟量化了参数效应。  相似文献   

19.

Heterogeneity in a population with respect to mortality, or variation in “frailty”; among members of that population, which has been discussed extensively in the literature over the last decade and a half is essential to any realistic model of dependence among causes of death. The main problem then is the development of a mortality model incorporating heterogeneity and cause of death which is both realistic and of manageable proportions.

In a recent paper (J. H. Pollard, 1991), it has been shown that many life table results are remarkably insensitive to the strict shape of the mortality curve, at least for more developed populations, and that accurate approximations can in many cases be obtained knowing only the mortality rates at two representative ages (e.g. 50 and 70). These results and the Gompertz “law”; of mortality can be used to develop manageable approximate formulae for the expectation of life under heterogeneity and correlation among the causes of death. The formulae are confirmed by simulation.

Numerical results indicate, somewhat surprisingly, that the effects of correlation among causes of death, even at quite high levels, on expectation of life and changes on expectation of life when particular causes of death are reduced or eliminated are relatively minor.  相似文献   

20.
The rate of mortality increase with age tends to slow down at very old ages. One explanation proposed for this deceleration is the selective survival of healthier individuals to older ages. Data on mortality in Sweden and Japan are generally compatible with three predictions of this hypothesis: (1) decelerations for most major causes of death; (2) decelerations starting at younger ages for more “selective” causes; and (3) a shift of the deceleration to older ages with declining levels of mortality. A parametric model employed to illustrate the third prediction relies on the distinction between senescent and background mortality. This dichotomy, though simplistic, helps to explain the observed timing of the deceleration.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号