Fertility decline in a US population favoring large families: A hazard-model analysis of the effect of sib death on Amish fertility

This paper uses proportional hazards techniques and population data from a directory of the Old Order Amish of the Lancaster, PA settlement. It examines the effect of death of the immediately prior sibling on the risk of childbearing for up to 11 children. Prior research typically has pooled data for maternal cohorts. In contrast, separate models are estimated for each maternal cohort. The results are based on all reported first marriages of Amish women born between 1884–1973 (N = 4066). Hazard models run separately for children of each birth order reveal that net of maternal age and length of the prior birth interval (and other statistical and design controls), the death of the prior sib significantly increases the risk of a subsequent birth for the lower birth orders. Separate models by maternal cohort show that sib death increases the risk primarily for later cohorts. The pattern of effects from child mortality and other variables suggests changes in fertility behavior among the Amish, who have strong, traditional norms opposing contraception and favoring large families.     

Demographic transitions: analyzing the effects of mortality on fertility

The effect of mortality reductions on fertility is one of the main mechanisms stressed by the recent growth literature in order to explain demographic transitions. We analyze the empirical relevance of this mechanism based on the experience of developed and developing countries since 1960. We distinguish between the effects on gross and net fertility, take into account the dynamic nature of the relationship, and control for alternative explanatory factors and for endogeneity. Our results show that mortality plays a large role in fertility reductions, that the change in fertility behavior comes with a lag of about 10 years and that both net and gross fertility are affected. We find comparatively little support for explanations of the demographic transition based on changes in GDP per capita.     

A new method for estimating the level of natural fertility in populations practicing birth control

The natural fertility schedule of a population is the schedule of age-specific marital fertility we would observe if no birth control were being practiced. In natural fertility (no birth control) populations we can observe the natural fertility schedule directly, but in populations practicing birth control the natural fertility schedule is disguised by the marital fertility rates in those age intervals in which control is exercised, the marital fertility rates being below the natural rates. This paper elaborates a method for estimating the natural fertility schedules of populations practicing birth control. Two alternative models are presented, one nonlinear and one linear. The use of these models is then illustrated with reference to the Old Order Amish population of Lancaster County, Pennsylvania. It is shown that for Amish women born between 1860 and 1900 both the nonlinear and linear models yield an estimate of .843 as the ratio between Amish and Hutterite natural fertility schedules.     

Direct and indirect effects on infant mortality in a high-fertility US population

This article examines the direct and indirect effects of social and demographic measures on infant mortality using data from a church directory of the Old Order Amish of the Lancaster, PA, Settlement. The sample includes all infant deaths and a simple random sample of survivors (total n=2013). The results reveal that the death of the immediately prior sibling directly increases the risk of infant death nearly 30%, net of other factors. Also, the risk of mortality in the first year increases as birth order increases, particularly at the highest orders (8–17 prior sibs). Infants of the youngest mothers (age 13) are nearly 10% more likely to die in the first year of life than are infants of mothers age 24, nearly all of which is indirect via parity, prior sib death and birth interval. Further analysis shows that families adapting more rapidly to external community pressures face a higher risk of infant death than families living in more stable areas. These relationships emerge even in this homogeneous population with a relatively high standard of living and a traditional lifestyle, Implications are that indirect effects should be included in research on teen pregnancy and infant survival, and might be especially important for studies in transitional geographic areas.An earlier version of this paper was presented at the 1993 meetings of Population Association of America, Cincinnati.     

Theoretical consideration of effect of fishing mortality on growth and reproduction of fish populations

Summary An increase in fish mortality due to fishing can theoretically change the growth and reproduction of fish populations from the viewpoint of adaptation. We address the issue of how an iteroparous fish should convert surplus energy into somatic growth and reproduction at each age under given conditions of mortality. A model of life history, which maximizes the net reproductive rate using the discrete maximum principle, is improved employing a new relationship between body weight and surplus energy which we have recently proposed. The model is applied to the North Sea plaicePleuronectes platessa, for which it has been reported that the average length of young fish had increased whereas that of old ones had decreased for some decades. Although the model cannot directly explain the former phenomenon, the two phenomena can be interpreted as a change in the optimal life history due mainly to an increase in mortality.     

The environment as a determinant of child mortality among migrants in frontier areas of Pará and RondÔnia, Brazil, 1980

This article examines child mortality as an indicator of the quality of life among migrants living in Brazilian Amazonia in 1980. I focus on migrants in the frontier states of Pará and RondÔnia, which experienced rapid settlement during the 1970s. The key question here is the effect of settlement location on child mortality rates. While RondÔnia had lower ratios of population per public health establishments and personnel than Pará, RondÔnia nonetheless exhibited a higher malaria prevalence in 1980. I therefore attribute locational differences in child mortality to environmental factors important to malaria transmission rather than to health care infrastructure. The findings from multivariate regression analysis show that net of the effects of human capital, migration history and migrant living standards, settling in Pará rather than RondÔnia resulted in significantly lower rates of child mortality. These findings suggest that environmental factors coinciding with location of frontier settlement had important consequences for the living standards of migrants in the Brazilian Amazon.     

Economic development and fertility

Two schools of theorists have been concerned with the effect of economic development on fertility. One school has contended that economic development has an inhibiting effect on fertility. The demographic transition which has occurred among the non-developed countries confirms their viewpoint. Another school of thought, including in its members Thomas Malthus, has believed that economic development promoted fertility. Much empirical evidence may also be brought to bear to support this viewpoint.The present paper attempts to reconcile these viewpoints. It is hypothesized that the direct effect of economic development is to increase fertility. However, various factors which usually accompany the process of economic development serve to reduce fertility. These include an increase in the level of education and a reduction in infant and childhood mortality. Making use of data for 41 nations pertaining to the decade of the 1950's, it is found that fertility is directly associated with per capita net national product when controls for other relevant variables are in8tituted. On the other hand, per capita newspaper circulation is inversely related to fertility, and infant mortality is directly related.If the hypothesis advanced in this paper is correct, relatively large governmental expenditures on health and education will enhance the reduction in fertility obtainable from an increase in national economic level alone.     

Family limitation among the Old Order Amish

Summary This paper shows that the Indiana Amish, a high-fertility Anabaptist population, regulate their marital fertility according to their family finances. We linked demographic data from the Indiana Amish Directory with personal property tax records at 5, 15 and 25 years after marriage and found fertility differences by occupation and wealth. Correlations between family size and wealth at the beginning, middle and end of childbearing years were positive. Wealthier women exhibited higher marital fertility, had longer first birth intervals, were older at the birth of their last child, and had larger families than poorer women. Over the past 30 years, marital fertility has remained constant among older women; but birth rates among younger women have been rising rapidly.     

Impact factors of purse seine net and dip net fisheries on a chub mackerel population

There are two major kinds of fisheries for the chub mackerel in Japan. The purse seine net fishery exploits young and adult fish during the foraging season, while the dip net fishery exploits fish before and during the spawning season. To compare the damage to the chub mackerel stock caused by purse seine net and dip net fisheries, we introduced impact factors of the two kinds of fisheries on the two kinds of fisheries and estimated number of eggs spawned in 1982. We defined the impact factor as the ratio of the average reproductive value of individuals caught by each fishery to the reproductive value at maturity. The number of individuals caught by the purse seine net fishery was 66 times larger than the number caught by the dip net fishery, while the impact factor of the former was 84% of that of the latter. Thus, the total damage caused by the purse seine net fishery was much higher than the damage caused by the dip net fishery. We can evaluate the damage caused by mortality factors on endangered species using this method.     

Estimation of a structural model of the determinants of neonatal mortality in Hungary, 1984-88 and 1994-98

We developed and evaluated a structural model of the determinants of neonatal mortality in Hungary that embodies the causal mechanisms by which its proximate and indirect determinants--socio-economic, behavioural, and biological--are related. The statistical model used distinguishes between endogenous and exogenous variables and allows the causal effect of each to be correctly estimated. Unobserved variables are integrated into the model, which was tested using Hungarian data for the periods 1984-88 and 1994-98. The principal findings are as follows: weight at birth and duration of gestation are the most important of the (direct) causal determinants of neonatal mortality. Mother's age has an indirect and detrimental effect: when mothers are older than 30 years of age, the risk of lower birth weight or multiple births and, in consequence, neonatal mortality is increased. Father's age has no direct or indirect causal effect on neonatal mortality.     

Estimating a marriage matching model with spillover effects

We use marriage matching functions to study how marital patterns change when population supplies change. Specifically, we use a behavioral marriage matching function with spillover effects to rationalize marriage and cohabitation behavior in contemporary Canada. The model can estimate a couple's systematic gains to marriage and cohabitation relative to remaining single. These gains are invariant to changes in population supplies. Instead, changes in population supplies redistribute these gains between a couple. Although the model is behavioral, it is nonparametric. It can fit any observed cross-sectional marriage matching distribution. We use the estimated model to quantify the impacts of gender differences in mortality rates and the baby boom on observed marital behavior in Canada. The higher mortality rate of men makes men scarcer than women. We show that the scarceness of men modestly reduced the welfare of women and increased the welfare of men in the marriage market. On the other hand, the baby boom increased older men's net gains to entering the marriage market and lowered middle-aged women's net gains.     

Household income and child survival in Egypt

This article uses household-level economic and fertility survey data to examine the relationship between household income and child survival in Egypt. Income has little effect on infant mortality but is inversely related to mortality in early childhood. The relationship persists with other associated socioeconomic variables controlled. The mechanisms underlying the income effects are not evident from this analysis: income differentials in sources of household drinking water, type of toilet facilities, and maternal demographic characteristics do not explain the net impact of income on child mortality. The absence of effects on child survival of the size of the place of residence and the relatively weak effects of maternal schooling are also notable.     

Estimating seasonality effects on child mortality in Matlab,Bangladesh

This paper estimates the net effect of seasonality on child mortality in Matlab. Results suggest that childhood mortality was well above the average monthly level in the hot, dry month of April and in November, the first harvest month of the aman crop. It was found to be remarkably low in the post harvest months of February and March. and also in August. During the hungry months of September and October, children were at a considerably increased risk of mortality. particularly from diarrheal diseases, if mothers had no schooling. but this was not the case if mothers had schooling. The protective effect of the Matlab interventions on childhood death from diarrheal diseases was also greater during the hungry months than during other months of the year.     

The effect of long-term migration dynamics on population structure in England & Wales and Scotland

We investigated the effect of migration on population dynamics in England & Wales and Scotland from the mid-nineteenth century to the present by comparing actual population size and structure with estimates based on zero net migration from a range of starting dates. In this period, Scotland had the largest net outflow among countries in Europe for which detailed information is available, whereas overall net migration in England & Wales was close to zero. In the absence of migration, population would have been over twice as large in Scotland in 2013 as the actual value, but similar to its actual value in England & Wales. Levels and pace of population ageing have been broadly similar in both countries, so the major impact of differential migration has been on population size rather than structure. We discuss these findings in relation to the debate on migration policy between political parties supporting and opposing independence in the 2014 Scottish referendum.     

The completeness of enumeration in the 1973 census of the population of Colombia

The effort is made to determine the true size and distribution by age and sex of the population of the Republic of Colombia in October 1973. After initially arriving at estimates of the levels of fertility and mortality during the intercensal period and then correcting the 1964 census population for age misreporting and selective undernumeration of males, a hypothetical populaiton corresponding to October 1973 is constructed. Comparing the constructed population with the population observed in the census yelds an estimate of completeness of enumeration in 1973 that is relative to the enumeration of females in 1964. This estimate is obtained under the assumption that net international migration during the period was of negligible importance. As there is reason to believe that this is not a valid assumption and upon examining the limited amount of evidence available, speculaitons are made concerning the amount of net out-migration to have occurred during the 1964-1973 period and the size of the coresponding modificaiton in the estimate of completeness of enumeration. After adjusting for underenumeration of males in 1964 and neglecting the impact of international migration, a theoretical 1973 census population of 23,201,000 was estimated. Apart from the total number of people enumerated, the information that was analyzed from the advance sample appears to be of good quality, at least in relation to prior censuses. The estimates of fertility and mortality reveal an important decline in Colombian fertility. By coming up with separate estimates of infant and childhood and adult mortality, it has been possible to shed new light on the shape and the level of mortality in Colombia. The new Brass method for estimating adult mortality provides reliable results even when mortality has been declining, and there are recognizable distortions in the distribution of the population by age.     

A Multistate model of fecundability and sterility

This paper develops a multistate hazards model for estimating fecundability and sterility from data on waiting times to conception. Important features of the model include separate sterile and nonsterile states, a distinction between preexisting sterility and sterility that begins after initiation of exposure, and log-normally distributed fecundability among nonsterile couples. Application of the model to data on first birth intervals from Taiwan, Sri Lanka, and the Amish shows that heterogeneity in fecundability is statistically significant at most ages, but that preexisting sterility and new sterility are unimportant before age 40. These results suggest that sterility may not be an important determinant of natural fertility until later reproductive ages.     

Migration and Intergenerational Replacement in Europe

There are long‐standing concerns over low fertility levels in Europe and an increasingly important debate on the extent to which migration can compensate for below‐replacement fertility. To inform this debate, a wide array of indicators have been developed to assess the joint influence of fertility, mortality, and migration on birth replacement and intergenerational replacement. These indicators are based on various models and assumptions and some are particularly data demanding. In this article we propose a simple method to assess how far migration alters the extent of replacement for a birth cohort as it ages. We term the measure the overall replacement ratio (ORR). It is calculated by taking the size of a female birth cohort at selected ages divided by the average size of the cohorts of mothers in the year of birth. We present estimates of the ORR for a range of European countries representing different replacement regimes. We demonstrate that for many countries net migration has become a key factor in their population trends during the last few decades.     

Different demographic changes and patterns of trade in a Heckscher–Ohlin setting

We examine the effects of different aging speeds on international trade patterns in an open overlapping generations model. An expansion in life expectancy of a country does not necessarily make the country a net exporter of capital-intensive goods when fertility is endogenous, depending on the relative magnitudes of the positive Rybczynski effect of changes in the factor endowments and the negative effect from the consumption–savings choice on the relative price in the autarkic steady state. The incidence of gains from trade among generations after opening trade depends on whether the country becomes a net exporter or importer of capital-intensive goods.     

The effect of number of siblings on adult mortality: Evidence from Swedish registers for cohorts born between 1938 and 1972

Demographic research has paid much attention to the impact of childhood conditions on adult mortality. We focus on one of the key aspects of early life conditions, sibling group size, and examine the causal effect of growing up in a large family on mortality. While previous studies have focused on low- or middle-income countries, we examine whether growing up in a large family is a disadvantage in Sweden, a context where most parents have adequate resources, which are complemented by a generous welfare state. We used Swedish register data and frailty models, examining all-cause and cause-specific mortality between the ages of 40 and 74 for the 1938–72 cohorts, and also a quasi-experimental approach that exploited multiple births as a source of exogenous variation in the number of siblings. Overall our results do not indicate that growing up in a large family has a detrimental effect on longevity in Sweden.     

The fiscal impact of immigration to welfare states of the Scandinavian type

In this paper, we examine the potential of immigration to strengthen fiscal sustainability, which is under pressure by an ageing population in many European countries. We look at a particularly challenging case, namely that of Denmark, which has extensive tax-financed welfare programmes that provide a high social safety net. The analysis is based on a forecast of the entire Danish economy made using a dynamic computable general equilibrium model with overlapping generations. We present life cycle estimates of the potential fiscal impact of immigration considering the cost of immigration on the margin as well as on average. The main conclusion is that immigrants from Western countries have a positive fiscal impact, while immigrants from non-Western countries have a large negative one, which is also the case when considering only non-refugee immigrants. The negative effect is caused by both a weak labour market performance and early retirement in combination with the universal Danish welfare schemes.