Cohort fertility differences between men and women in a developed population: Evidence from Spain

This paper discusses the use of unmeasured variables in path models. Problems of estimation of the path coefficients of a path model are explored when unmeasured variables are utilized as both causes and effects (intervening variables). The paper concludes with a discussion of conditions for the identification of a path model containing unmeasured variables and some remarks on the substantive interpretation of unmeasured variables.

Razlike u kohortnom fertilitetu prema migracijskom obilježju: slučaj Grada Zagreba

This study attempts to analyze the levels and patterns of cohort fertility in Nepal in 2016 using data on parity progression ratios (PPRs). Simple PPRs, rather than synthetic PPRs or birth history of women, are used in this study from distribution of women by age and children ever born. Data on PPRs are used from 2016 Nepal Demographic and Health Survey to estimate cohort fertility of currently married and all women separately. Fertility is analyzed for different birth cohorts of women, specifically for birth cohorts of age groups 45-49, 20-24, 25-29, and 30-34 years, beside overall span of reproductive ages (15-49) for different purposes. The PPRs data are employed in this study in three different ways such as PPRs itself, proportion of women with at least ‘N’ number of children ever born (CEB), and cohort fertility rates. All three measures are implied to estimate cohort fertility of both currently married and all women separately. Fertility patterns are almost similar in all the three methods and other the measures show that the level of cohort fertility is still a little higher in Nepal, although it is declining gradually over time. The completed cohort fertility is estimated at around 4 in Nepal in 2016. The contribution of this article will be to check fertility level by applying this simple, but less common, method in estimating cohort fertility.

For the analysis of fertility trends the author draws upon official data and presents a preview of some of the materials in P. K. Whelpton's forthcoming monograph: Cohort Fertility: Native White Women in the United States. His discussion of trends in fertility differentials since 1940 is based mainly upon the Census Bureau's periodic releases giving fertility ratios among groups sampled in the Current Population Survey during the past few years.

BACKGROUND: The long-term decline in cohort fertility in highly developed countries has been widely documented. However, no systematic analysis has investigated which parity contributed most to the fertility decline to low and very low levels. Objective: We examine how the contribution of changing parity progression ratios varied across cohorts, countries, and broader regions in Europe, North America, Australia, and East Asia. We pay special attention to countries that reached very low completed cohort fertility, below 1.75 children per woman. Methods: Using population censuses and large-scale surveys for 32 low fertility countries, we decompose the change in completed cohort fertility among women born between 1940 and 1970. The decomposition method takes into account the sequential nature of childbearing as a chain of transitions from lower to higher parities. Results: Among women born between 1940 and 1955, the fertility decline was mostly driven by reductions in the progression ratios to third and higher-order births. By contrast, among women born between 1955 and 1970, changes in fertility showed distinct regional patterns: In Central and Eastern Europe they were fuelled by falling second-birth rates, whereas in the German-speaking countries, Southern Europe, and East Asia decreases in first-birth rates played the major role. Conclusions: Pathways to low and very low fertility show distinct geographical patterns, which reflect the diversity of the cultural, socioeconomic, and institutional settings of low fertility countries. Contribution: Our study highlights the importance of analysing parity-specific components of fertility in order to understand fertility change and variation. We demonstrate that similar low levels of completed cohort fertility can result from different combinations of parity-specific fertility rates.

BACKGROUND: The long-term decline in cohort fertility in highly developed countries has been widely documented. However, no systematic analysis has investigated which parity contributed most to the fertility decline to low and very low levels. Objective: We examine how the contribution of changing parity progression ratios varied across cohorts, countries, and broader regions in Europe, North America, Australia, and East Asia. We pay special attention to countries that reached very low completed cohort fertility, below 1.75 children per woman. Methods: Using population censuses and large-scale surveys for 32 low fertility countries, we decompose the change in completed cohort fertility among women born between 1940 and 1970. The decomposition method takes into account the sequential nature of childbearing as a chain of transitions from lower to higher parities. Results: Among women born between 1940 and 1955, the fertility decline was mostly driven by reductions in the progression ratios to third and higher-order births. By contrast, among women born between 1955 and 1970, changes in fertility showed distinct regional patterns: In Central and Eastern Europe they were fuelled by falling second-birth rates, whereas in the German-speaking countries, Southern Europe, and East Asia decreases in first-birth rates played the major role. Conclusions: Pathways to low and very low fertility show distinct geographical patterns, which reflect the diversity of the cultural, socioeconomic, and institutional settings of low fertility countries. Contribution: Our study highlights the importance of analysing parity-specific components of fertility in order to understand fertility change and variation. We demonstrate that similar low levels of completed cohort fertility can result from different combinations of parity-specific fertility rates.

Patient survival on dialysis in Korea: a different story?

Studies of immigrant fertility differentials indicate that foreign-born women have more children than native-born women, at least for some origin groups. Yet little is known about variation in cumulative fertility differentials over the life course, including the extent to which this variation develops into completed fertility differentials. This research responds with an analysis of cumulative fertility differentials in the UK for a cohort of women born between 1942 and 1971. Findings are consistent with age-specific patterns that have been documented for immigrant groups in the UK, but underline the importance of taking a cohort perspective, which helps to distinguish between the tempo and quantum of fertility. Immigrants have significantly higher completed fertility than UK-born natives if they were born in India, Pakistan, Bangladesh, Jamaica, or Western and Central Africa, but the profile of their cumulative fertility differentials—versus the UK-born—varies considerably over the life course, especially by age at migration. For example, women from Bangladesh and Pakistan have similar levels of cumulative fertility at age 40, but very different age patterns of cumulative fertility from ages 20–40. There is a consistent pattern of relatively delayed Pakistani fertility at early ages, especially for those arriving at later ages, but the same is not true for women from Bangladesh. Overall, these results imply that researchers should beware of variation in cohort fertility over the life course—with respect to both the quantum and tempo of fertility—when analysing immigrant childbearing, in addition to variation by origin and age at arrival.

This study analyses trends in cohort fertility in the former Yugoslav countries. The goal is to identify and describe differences and similarities in demographic trajectories related to fertility behaviour. We consider a relatively long period, covering the transformation from agrarian to industrial capitalist societies during the late nineteenth and early twentieth centuries, and continuing with a rapid transition into socialist modernity after 1945. This era witnessed profound societal, political, and economic changes that strongly influenced fertility behaviour in the region, with key roles played by changes in women’s roles, urbanization, and other socio-economic and socio-cultural factors crucial for family life. Our inquiry further extends to the more recent period, and examines how fertility-related demographic trajectories developed over the transition to the market economy during the 1990s and beyond. We aim to provide a detailed overview of cohort fertility patterns in former Yugoslav states, to detect countries with similar characteristics, and to assess the potential convergence among countries. Drawing data on the number of live births from the post-World War II censuses, we calculate and present indicators on completed cohort fertility rates, parity progression ratios, and parity distribution. Our findings indicate that fertility decline in former Yugoslav republics took place at varying paces and in different ways, and that the progression to higher birth orders played a crucial role in shaping the identified patterns. Employing cluster analysis, we identified three distinct groups of countries, with Croatia, Slovenia, and Serbia forming the low-fertility group. Bosnia and Herzegovina, North Macedonia, and Montenegro exhibited higher fertility levels, and Kosovo represents a unique example of a country with exceptionally high fertility in Europe. The results highlight the intricate interaction of historical, political, economic, and social factors that contribute to the observed clustering of countries. Our comprehensive analysis contributes to a better understanding of persisting differences and potential convergence in cohort fertility trends in the former Yugoslav region.

Can medically assisted reproduction (MAR) compensate for completed cohort fertility (CCF) decline within coresidential unions due to increasing maternal ages among Dutch women born during 1974-1984? MAR is unlikely to compensate for cohort fertility decline within coresidential unions due to continued increase in maternal ages in our sample cohort of Dutch women born during 1974-1984, even under ideal conditions. The pregnancy- and live birth rates for both expectant management and MAR decline at older reproductive ages. Some infertile couples can conceive naturally without undergoing treatment by trying to conceive for a longer period of time, which complicates estimating the contribution of MAR to cohort fertility. We developed a microsimulation model, which includes MAR, that simulates the reproductive life courses of women. We simulate a sample of 1000000 women representing the 1974-1984 Dutch birth cohort. Sample sizes for the input parameters varied from hundreds to thousands to hundreds of thousands depending on the parameter and source (surveys, clinical studies, panel data, population registers). Our Monte Carlo microsimulation model uses probability distributions and parameters based on representative data sources to determine a woman's transitions through union and reproductive events across her reproductive life course. We assess the contribution of various components of the MAR process to CCF within coresidential unions and estimate the net contributions of MAR to CCF with counterfactual simulations. Increases in the maximum female age at MAR treatment, the time to starting IUI treatment, and the number of IUI cycles did not noticeably increase CCF. Out of the hypothetical policy levers that were adjusted, increasing the share of eligible women who took up MAR from 0% to 100% increased CCF linearly by 0.06 children. Increasing the waiting time to ART treatment after infertility diagnosis from 1 to 12 months reduced CCF by 0.01. Increasing the number of reimbursed IVF/ICSI cycles from 0 to 6 increased CCF by 0.05. The increase tapered off after cycle number 2, and levelled off after cycle number 4. Minimum ages at which MAR treatment was started that were between 20 and 30 resulted in near-identical patterns of change in CCF from the adjustment in the potential policy levers, whereas both the CCF levels and rate of increase or decline were reduced at age 35years, and further at age 40years. The main influences on the lower CCF levels and slower rate or increase or decline were the reduction in MAR pregnancy rates at advanced reproductive ages, the increasing probability of intrauterine mortality with age, and time spent trying to conceive naturally before starting MAR treatment. The net contribution of MAR (0.043 children per woman, 2.5% to non-MAR CCF) was 33% smaller than the observed MAR birth share of CCF (0.064 children per woman, 3.7% of simulated CCF including MAR). The relative contribution of MAR was strongest at ages 35-39 (6.0%) and at age 40years and above (8.6%), and weakest at ages 20-24 (0%) and 25-29years (1.0%). In absolute number of children born, most of the contribution of MAR occurred at ages 30-34 (0.016 children) and ages 35-39years (0.015). The Monte Carlo variation in the simulation model was measured to be around ±0.001 based on 10 simulations of 1000000 women. Parameter uncertainty was accounted for where possible by allowing parameters to vary within nonparametrically bootstrapped values generated from the sample data. Our model cannot fully capture the complexity of the fertility and MAR processes with regards to factors like infertility diagnosis, partner characteristics, and health status. Due to missing information, an extensive number of parameters, and limited sample sizes when estimating some of the parameters; the model output deviates slightly from the reference data. We cannot establish causality due to endogeneity in the modelling. We are not entirely confident in the zero contribution of IUI, because clinical data suggest that IUI pregnancy rates are higher than expectant management pregnancy rates, but the quality of that clinical data is low and sparse. The scope of the study is limited to births within coresidential unions, because information on unions and births outside of coresidential union was insufficient for modelling purposes. While MAR remains an important tool to address infertility, our results suggest that it is unlikely to compensate for population fertility decline attributable to postponement of childbearing to older reproductive ages. Failing to account for the counterfactual case that some couples who undergo MAR may conceive naturally given longer expectant management may lead to overestimation of the contribution MAR can make to population fertility. This work was supported by a VIDI grant (VI.Vidi.201.119) from the Netherlands Organization for Scientific Research to G.S. A.H. reports consulting fees by Ferring Pharmaceutical company The Netherlands, paid to institution UMCG, not related to the presented work. N/A.

Educational differences in female cohort fertility vary strongly across high-income countries and over time, but knowledge about how educational fertility differentials play out at the sub-national regional level is limited. Examining these sub-national regional patterns might improve our understanding of national patterns, as regionally varying contextual conditions may affect fertility. This study provides for the first time for a large number of European countries a comprehensive account of educational differences in the cohort fertility rate (CFR) at the sub-national regional level. We harmonise data from population registers, censuses, and large-sample surveys for 15 countries to measure women’s completed fertility by educational level and region of residence at the end of the reproductive lifespan. In order to explore associations between educational differences in CFRs and levels of economic development, we link our data to regional GDP per capita. Empirical Bayesian estimation is used to reduce uncertainty in the regional fertility estimates. We document an overall negative gradient between the CFR and level of education, and notable regional variation in the gradient. The steepness of the gradient is inversely related to the economic development level. It is steepest in the least developed regions and close to zero in the most developed regions. This tendency is observed within countries as well as across all regions of all countries. Our findings underline the variability of educational gradients in women’s fertility, suggest that higher levels of development may be associated with less negative gradients, and call for more in-depth sub-national-level fertility analyses by education.

Educational differences in female cohort fertility have been shown to vary across high-income countries and over time, but knowledge about how educational fertility differentials play out at the sub-national regional level is limited. Examining these sub-national regional patterns might improve our understanding of national patterns, as regionally varying contextual conditions may affect fertility. This study provides for the first time for a large number of European countries a comprehensive account of educational differences in the cohort fertility rate (CFR) at the sub-national regional level. We harmonise data from population registers, censuses, and large-sample surveys for 15 countries in order to measure women’s completed fertility by educational level and region of residence at the end of the reproductive lifespan. In order to explore associations between educational differences in CFRs and levels of economic development, we link our data to regional estimates of GDP per capita. Empirical Bayesian estimation is used to reduce uncertainty in the regional fertility estimates. Our results document an overall negative gradient between the CFR and level of education, and notable variation in the gradient across regions. The gradient varies systematically by the level of economic development: moving from less to more developed regions, we observe smallergradients both across countries and within countries. However, the within-country patterns of countries differ. Our findings underline the variability of educational gradients in women’s fertility, suggest that higher levels of development may be associated with less negative gradients, and call for more in-depth fertility analyses by education at the sub-national level.

Aims The limitations of classical Lotka–Volterra models for analyzing and interpreting competitive interactions among plant species have become increasingly clear in recent years. Three of the problems that have been identified are (i) the absence of frequency-dependence, which is important for long-term coexistence of species, (ii) the need to take unmeasured (often unmeasurable) variables influencing individual performance into account (e.g. spatial variation in soil nutrients or pathogens) and (iii) the need to separate measurement error from biological variation. Methods We modified the classical Lotka–Volterra competition models to address these limitations. We fitted eight alternative models to pin-point cover data on Festuca ovina and Agrostis capillaris over 3 years in an herbaceous plant community in Denmark. A Bayesian modeling framework was used to ascertain whether the model amendments improve the performance of the models and increase their ability to predict community dynamics and to test hypotheses. Important Findings Inclusion of frequency-dependence and measurement error, but not unmeasured variables, improved model performance greatly. Our results emphasize the importance of comparing alternative models in quantitative studies of plant community dynamics. Only by considering possible alternative models can we identify the forces driving community assembly and change, and improve our ability to predict the behavior of plant communities.

The productivity of mental health care: an instrumental variable approach.

Data are available for the first time for the year under report 2008 on the biological number of children of women from the comprehensive Microcensus sample. Previously, only the ongoing birth statistics provided information on cohort fertility as a total fertility rate of the synthetic female cohorts. Since both benchmarks bear different types of insecurity, a comparison is to provide important information on the quality of these indicators. This article shows that the average number of children per woman in the dataset of the Microcensus 2008 and the cohort fertility rate in the birth statistics show a highly similar course of cohort fertility. Whilst the agreement for the female cohorts in the new Länder (former GDR without Berlin East) and in Germany as a whole is almost complete, the values in the old Länder (Western Germany without Berlin West) are further apart. A major cause of this evidently lies in the high proportion of female immigrants in the old Länder. Some of the women who immigrated into the former territory of Federal Republic already gave birth to their children before entering Germany. These births could not be taken into account in the ongoing birth statistics, whilst the Microcensus provided information on all children born, regardless of where they were born. These survey-related deviations can be largely reduced if the comparison with the cohort fertility rate of the birth statistics is based not on the average number of children of all women, but only on the number of children of women who were born in Germany or who immigrated below the age of 26. The share of female migrants was low in the new Länder and did not impact cohort fertility. All in all, the comparison showed that both sets of statistics provide data with a good degree of concurrence on the fertility of the birth years from 1933 to 1992 for Germany as a whole, as well as for the old and the new Länder. This makes it possible to carry out detailed analyses of fertility in relation to comprehensive socioeconomic characteristics of the Microcensus.