Systematic and chance components in fertility measurement

Abstract A Monte Carlo simulation model of fertility is developed to incorporate a decline in fecundability with age of women as well as a variation between women, and a family planning strategy in which couples prefer certain sizes of families and seek to lengthen the last planned birth interval. In the simulation of family planning and non-family planning populations, segmental parity tables are computed. These are tables in which the numbers of women in the columns representing the completed family sizes are sub-divided by rows representing the sizes of the families for shorter durations of marriage. The couples' success in their plans, under various conditions, and the rapidity with which family sizes stabilize, are among the results obtained from the simulation. The application of the tables to the estimation of family size preferences from observed family size distributions is also discussed.     

Factors affecting oviposition rate in the flour beetleTribolium castaneum and the origin of the population regulation mechanism

Summary The effects of egg cannibalism, conditioned medium and the presence of quinone secretions on oviposition rate were studied using single pairs of adults to eliminate any direct crowding effects. Most measurements were made on beetles confined to the surface of the flour medium in plastic towers. Oviposition rate was decreased by about 58% when pairs were transferred from fresh to conditioned medium; lowered about 25% when only quinones were present and the medium was still fresh; and enhanced 35% in dry conditions when beetles were provided with eggs to eat. Both the lowered oviposition rate in confined cultures and egg-eating may be explained by natural selection at the individual level. Cannibalizing eggs boosts a female's oviposition rate. The presence of quinones or conditioned medium indicates high population densities and acts as a signal for ceasing oviposition and dispersing to avoid high egg mortality. In confined populations, this results in population regulation, while in open populations, this strategy is a mechanism to avoid competition. It implies that the resource shortages normally experienced by such organisms are relative, not absolute.     

Child mortality and reproductive behaviour in German village populations in the past: A micro-level analysis of the replacement effect

Abstract Reproductive histories of couples married during the eighteenth and nineteenth centuries in a sample of 14 German villages are analysed in order to answer several questions regarding the relationship between child mortality and reproductive behaviour. An effort is made through selection of cases and use of multiple classification analysis to eliminate or control non-volitional or otherwise confounding influences on the relationship between a couple's experience with child mortality and their fertility. The results do not provide a decisive answer to the question of whether, under a regime of otherwise presumed natural fertility, previous experience of child mortality affected subsequent reproductive behaviour. The evidence was much clearer in indicating that behaviour consistent with replacement efforts emerged or strengthened as family limitation spread. Finally, the results indicated that though it was not necessary for overall child mortality to decline before family limitation practices were adopted, couples with the most favourable child mortality experience were most likely to practise family limitation and to reduce their fertility. Child mortality appeared at least to impede, if not totally prevent, efforts to reduce the number of children ever born or to cease childbearing at an earlier age or at a given parity.     

The structural causes of infant mortality decline in Chile

The effect of macro processes on infant mortality rates is explored in this analysis of Chilean provincial statistics over five decades. Urbanization and pluralism, as measured by the percent of the population in urban centers and the percent voting, predict lower infant mortality strongly and consistently. The theoretical rationale for linking macrostructural variables to biological outcomes is then examined in more detail. It is argued that the structural model employed here is an improvement on the conventional modernization/biomedical explanation because of its greater consistency and specificity, and because inclusion of measures of health technology in the tests did not eliminate the effect of the structural variables.     

Estimation of sample size of population survey]

Depending on the different purposes of population surveys, different sample sizes are required for accurate results. Using statistical methods, sample sizes for different types of population surveys for the Chinese population are estimated. Thus, to insure at least 90% accuracy, a sample size of 830,000 is required for marriage and birth rates and a sample size of 7.8 million for population age distribution. For population surveys on age specific death rates, a sample size of 56.32 million is required for a 1-year retrospective study and a sample size of 11.26 million required for a 5-year retrospective study. In the past, certain population studies were undertaken with no consideration for sampling errors. Sample sizes for surveys on age specific death rates and population age distribution were too small, leading to results that did not represent the total population. On the other hand, sample sizes for marriage and birth conditions were too large, resulting in waste in manpower, materials, and time. Statistical calculations are given.     

The Impact of Family Size on Wealth Accumulation in Rural Thailand

Abstract. We examine the effect of socio-economic covariates on infant mortality in China in the 1980s, particularly the role of previous birth interval and mother's education, using an event history approach with data from the 1988 Two per Thousand Fertility Survey. We use a Bayesian model averaging strategy that takes account of model uncertainty as well as parameter uncertainty. A standard stepwise logistic regression analysis finds no statistically significant relationship between the preceding birth interval and infant survival after controlling for socio-demographic factors, but this finding is reversed when the Bayesian model averaging approach is adopted. However, the method finds less support than a standard stepwise approach for the role of mother's education. We consider the model-fitting criterion of predictive power when applied to out-of-sample observations, and show that Bayesian model averaging outperforms the stepwise approach. We conclude that, even with large sample sizes, the interpretation of results can vary substantially according to model selection and fitting criteria.     

On the tempo of childbearing in England and Wales

Abstract The paper describes a computerized model developed to simulate the fertility of a hypothetical marriage cohort in a closed population. The model was applied to England and Wales fertility data of marriage cohorts of the years 1951 to 1970. For each of these cohorts, the computer was programmed to construct five series of tables showing birth-order probabilities, family size frequency distribution, mean length of intervals between marriage and successive births, parity progression ratios and mean family sizes of fertile women. The results showed that the fertility of the cohorts of women who married between the middle 1950s and the early 1960s was character ized by a declining trend in the frequency of childlessness and by a dramatic increase in the proportion of marriages with two or more children. Since 1964 or so, there has been a downward trend in duration-specific birth-order probabilities. The analysis suggests that the recent drop in fertility may well prove to be the effect of an upward shift in the timing of births as well as a fall in completed fertility.     

试论儒家文化对我国人口与计划生育的影响

本文本着批判继承祖国文化遗产的宗旨 ,以《四书五经》及儒家其他书籍为研究对象 ,重点探讨和分析了儒家文化对我国人口与计划生育产生的正负面影响 ,并提出了消除其负面影响的相应对策     

Household dynamics and fuelwood consumption in developing countries: a cross-national analysis

Previous research has suggested a link between household dynamics (i.e., average household size and number of households) and environmental impacts at the national level. Building on this work, we empirically test the relationship between household dynamics and fuelwood consumption, which has been implicated in anthropogenic threats to biodiversity. We focus our analysis on developing countries (where fuelwood is an important energy source). Our results show that nations with smaller average households consume more fuelwood per capita. This finding indicates that the household economies of scale are, indeed, associated with the consumption of fuelwood. In addition, we found that number of households is a better predictor of total fuelwood consumption than average household size suggesting a greater relative contribution to consumption levels. Thus, insofar as declining average household sizes result in increased number of households and higher per capita consumption, this trend may be a signal of serious threats to biodiversity and resource conservation. We also found further support for the ??energy ladder?? hypothesis that economic development reduces demand for traditional fuels.     

Decomposition of the Shrinking Middle-class and Directional Mobility in Finland 1995–2012

This paper investigates the middle-class decline in Finland from 1995 to 2012. The purpose is to examine how changes in the probabilities of belonging to the middle class in different socioeconomic groups have contributed to the middle-class decline while taking into account changes in the relative sizes of the groups. A decomposition analysis indicates that most of the decline has been due to the probability effect, especially among the least-educated population. Changes in age demographics and educational structure have contributed to the decline. The results of the decomposition are supported by mobility results, which indicate that individuals with a tertiary (no secondary) degree have been subject to upward (downward) mobility over the observed time period. In conclusion, the middle-class decline and polarization in Finland are asymmetrically reflected in different education groups. The highly educated have climbed up the income distribution, while the least educated have fallen.

     

An Outcomes-Based Assessment of Quality of Life in Social Services

The goal of this article consists of describing the calibration of an instrument to assess quality of life-related personal outcomes using Rasch analysis. The sample was composed of 3.029 recipients of social services from Catalonia (Spain) and was selected using a probabilistic polietapic sample design. Results related to unidimensionality, item and person separation reliability, calibration, items’ level of difficulty, response categories and differential item functioning by gender and type of collective are provided and point out the general fit of the data to the model. However, it is recommended to include more difficult items and eliminate one that seems not to be adequate.     

A field study of the effect of prebaiting on censusing by the capture-recapture method in a vole population

Summary Populations of the vole,Clethrionomys rufocanus, in a lowland woodlot of Hokkaido were studied for the presence of effects of prebaiting on censusing by the capture-recapture method. A grid of 121 live-traps, spaced 5 m apart, was laid out on each of two plots, one of which alone was prebaited three days long. Owing to very high densities and great trap-efficiency, sufficient and favourable samples could be available for statistical analysis, except the trend of delayed catch for young in sampling. The population on either plot, however, proved to be markedly variable in catchability of unmarked animals in the course of trapping; while the probability of recapture was counted as invariable on the average from day to day, the recapture frequency was different between juveniles, subadults and adults. Needless to say, the catchability was distinctly greater for marked voles than for unmarked ones, whether prebaited or not, through the trapping period, except that the first-day catchability for unmarked ones on the prebaited plot seems not to be significantly lower than that for marked ones. Consequently, it turns out that the prebaiting has almost never helped to eliminate the important bias induced by differential trap-response of marked and unmarked animals; its contribution is only that the catchability for unmarked ones is slightly higher on the part of the prebaited plot on earlier days of the period. In accordance with the heterogeneous catchability, the Γ-form distribution analogous to the geometric could be applied with thorough fitness to the capture frequency in order to estimate the whole populations. The fact that the estimates are reliable, being not at any rate underestimates, was further confirmed by the result of a follow-up work conducted by means of the removal method with wider trap-spacing which brought forth distinct underestimation chiefly referable to unexposure to traps of the partial populations. The subject of unexposure was discussed by laying stress on the relation between minimum range length and trap-spacing. Contribution from JIBP-PT No. 88, carried out by the grant from the expenditure of Education Department to the specific study on “Dynamics of Biosphere”.     

Late marriage and the HIV epidemic in sub-Saharan Africa

The causes of large variation in the sizes of HIV epidemics among countries in sub-Saharan Africa are not well understood. Here we assess the potential roles of late age at marriage and a long period of premarital sexual activity as population risk factors, using ecological data from 33 sub-Saharan African countries and with individual-level data from Demographic and Health Surveys (DHS) in Kenya and Ghana in 2003. The ecological analysis finds a significant positive correlation between HIV prevalence and median age at first marriage, and between HIV prevalence and interval between first sexual intercourse and first marriage. The individual-level analysis shows that HIV infection per year of exposure is higher before than after first marriage. These findings support the hypothesis of a link between a high average age at marriage and a long period of premarital intercourse during which partner changes are relatively common and facilitate the spread of HIV.     

Results of a Quality of Work Life Index in Spain. A Comparison of Survey Results and Aggregate Social Indicators

The European Union launched the Lisbon Strategy in 2000 with the aim of establishing itself as the world’s most powerful economy. The importance of job quality has returned to the top of the European employment and social policy agenda. As targets are set, significant progress has been made in the creation of indicators. In this study, we compute a composite index for quality of work life using the dimensional structure provided by the European Commission, and present our results for regions, sectors, professional categories and sizes of firm in Spain in the period 2001–2004. We find that better results are found in the more developed regions, in service sectors, in bigger firms and in jobs with more responsibility. Finally, we compare the results of the index with workers’ subjective perceptions of job satisfaction, measured by a quality of work life survey. The test results reveal a strong relationship between the two measurements.     

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.     

The influence of rural-urban migration on migrants' fertility in Korea,Mexico and Cameroon

The paper presents a comparative analysis of the relationship between rural-urban migration and fertility in Korea, Mexico, and Cameroon. Using an autoregressive model, the results show a significant rural-urban migration adaptation effect in Korea and Mexico, a reduction of 2.57 and 1.45 children during the entire childbearing period, respectively, when compared to a rural stayer, even after the effect of selection has been controlled. Rural-urban migration has a very small impact on fertility in Cameroon. The unexpected result for Cameroon is due to the fact that the fertility-increasing effect of urban residency on the improved supply conditions of births, such as reduced infertility, offsets the fertility-depressing effect of urban residency on the demand for births. As a result of the adaptation to urban fertility norms, the number of country-wide births was reduced significantly in Mexico and Korea over the time periods studied.     

孕产妇死亡健康公平性分析

文章利用2000～2005年全国卫生统计年报中孕产妇死亡情况有关资料,计算了以孕产妇死亡率为基础的一系列健康公平性指标,分析了2000～2005年间我国孕产妇死亡的健康公平性。研究结果从人群归因危险度百分比、集中指数、集中曲线等指标反映出在我国孕产妇死亡存在分布的不均衡。2000～2005年我国孕产妇死亡在地区间及省际的差距没有明显变化,即不公平现象6年间没有得到改善。     

American Family Building Strategies in 1900: Stopping or Spacing

Contemporary populations frequently space the births of children, and also attempt to stop childbearing after achieving a desired family size. While stopping behavior was evident in European populations in the late nineteenth century, little is known about the degree to which they attempted to space their children at specific interval lengths. This paper compares spacing patterns among various groups of white U.S. women in 1900, who were distinguished by varying family sizes and levels of fertility control. On the whole, there is little evidence of childspacing differences among native white populations, except for some very low parity women. The findings support the continued analysis of age patterns of fertility as the major means for determining the onset of conscious family limitation.     

Size and structure of the household in England over three centuries

Abstract Data giving sizes and structures of households have been rare for any country before the institution of the official census, and have to be gleaned from surviving documents containing listings of inhabitants. This article, the first of two, describes the collection of listings of inhabitants of English communities which is being assembled by the Cambridge Group for the History of Population and Social Structure and the methods by which the hundred most informative of them have been submitted to analysis. When ranged alongside the information on mean household size derived from the official British census since its inception in 1801, the results of this analysis suggest the following. 1. Mean household size in England and Wales as a whole was relatively constant at 4·75 or a little below for the whole period from the sixteenth century until 19II, and has only fallen since that date. The reduction of about one-third starting in 1921 may therefore be the first of considerable magnitude ever to occur: it seems to have been particularly rapid between 1911 and 1931. 2. Mean household size in England and Wales has been surprisingly resistant to demographic fluctuation on the one hand and to the structural influences of industrialization on the other, until the last fifty or sixty years. 3. The traditional household in England has never been extended on any definition, at least since the sixteenth century. Mean household size varied with social status, and a majority lived in households of six or more members. But this distribution was due to the very large numbers of servants living in and not to the presence of resident kin, who seem to have been rare. 4. The relationship between fertility, mortality and mean household size is different from what has been supposed. This article ends by registering the paradox that proportion of children in a pre-industrial English community apparently seems to be negatively, not positively, related to its mean household size, and this theme will be taken up in the second article. These four points are illustrated by a series of tables drawn from the analysis of the one hundred communities.     

Immigration cohorts and residential overcrowding in southern California

To what degree do immigrants reduce their high rates of residential overcrowding with increasing length of residence in the United States? This question is addressed through the application of a “double cohort” method that nests birth cohorts within immigration cohorts. This method enables duration of immigration effects to be separated from aging effects as cohorts pass through life course phases, when family sizes may be growing or shrinking. The analysis finds that cohort trends differ sharply from the cross-sectional pattern observed at a single point in time. Cohorts’ growth in income is found to contribute substantially to the decline in overcrowding over time. Cohort trends among Hispanic immigrants, however, diverge from those among others, indicating much less decrease in overcrowding and even increases over certain age spans.