Registration completeness and international comparisons of infant mortality

The physical development of the live born infant is the single most important variable governing its survival: infant mortality among those weighing 2,500 grams (5 1/2 pounds) or less at birth is 17 times the mortality among those weighing more than 2,500 grams at birth. The variation in mortality according to birth weight (or gestation) is greater than for subclasses of color, sex, maternal age, or birth order. Infant mortality in the United States is significantly higher than in a number of other countries e.g., Sweden, Netherlands, Norway. The difference is thought, by some, to be due to underregistration of low birth weight infants in other countries. In this paper, distributions of live births by birth weight for Denmark, England and Wales, New Zealand, and the United States, and infant mortality data for Denmark and the United States are examined. The data do not support a hypothesis of gross underregistration of live born infants in other countries. The results indicate that some index of physical development (birth weight, gestation, or a combination of both) should be included in any appraisal of infant mortality.     

A model of numbers of births in three countries,with persistent forty-year cycles

This paper describes a model which relates fertility to partner availability, an aspect of relative cohort size. Partner availability is affected by the tendency for males to reproduce at a later age than females. For women born at a time of rising birth rates, there is a shortage of slightly older men as potential partners. Women born when birthrates are falling enjoy a surplus of older men from which to choose. This model is believed to be the first non-linear demographic feedback model involving feedbacks through marriage squeezes in which empirically estimated values of the parameters imply persistent limit cycles. The deterministic model makes births in each five-year period a function of births in previous five-year periods. The form of the function is chosen to model the effect of partner availability upon entry into reproductive relationships, and therefore on age-specific fertility. Marriage rates are not modeled directly. The model was developed from data for more than a century from England and Wales, New Zealand, and the US. The demographic transition is modeled with a logistic function and age-specific fertility rates are estimated using lognormal distributions. The stepwise inclusion of a partner availability estimate in the model showed that it accounts for 29% of otherwise unexplained variance. Projected future births stabilize in sustained or limit cycles with periods a little longer than 40 years, and amplitudes of at least 7% of the mean. The necessary conditions for cycle persistence are outlined on a graph of maximum and minimum fertility parameters.     

A model of numbers of births in three countries,with persistent forty‐year cycles

A non‐linear model of fertility is described, which was derived from data for more than a century from England and Wales, New Zealand, and the U.S.A. The demographic transition is modelled with a logistic function, and age‐specific fertility rates are estimated using lognormal distributions. The stepwise inclusion of a partner availability estimate in the model showed that it accounts for twenty‐nine percent of otherwise unexplained variance. Projected future births stabilise in sustained or limit cycles with periods a little longer than 40 years, and amplitudes at least 7% of the mean. The necessary conditions for cycle persistence are outlined on a graph of maximum and minimum fertility parameters.     

The effects of temperature on human fertility

Monthly birth and temperature data for a variety of states and countries are used to estimate the effect of short-run temperature fluctuations on fertility. Regressions of monthly births on a flexible specification of lagged monthly temperature show that temperature has quantitatively important effects on both seasonal and nonseasonal variation in births. Summer temperature extremes reduce conceptions in the southern United States, explaining a substantial part of the observed seasonal birth pattern. Extreme cold shows no evidence of affecting conceptions. The results also show significant seasonality in births even after accounting for temperature. Controls for monthly temperature do not explain the persistent spring peak in births in northern Europe. This finding suggests that other factors play an important role.     

Education Gains Attributable to Fertility Decline: Patterns by Gender,Period, and Country in Latin America and Asia

We investigate the heterogeneity across countries and time in the relationship between mother’s fertility and children’s educational attainment—the quantity-quality (Q-Q) trade-off—by using census data from 17 countries in Asia and Latin America, with data from each country spanning multiple census years. For each country-year, we estimate micro-level instrumental variables models predicting secondary school attainment using number of siblings of the child, instrumented by the sex composition of the first two births in the family. We then analyze correlates of Q-Q trade-off patterns across countries. On average, one additional sibling in the family reduces the probability of secondary education by 6 percentage points for girls and 4 percentage points for boys. This Q-Q trade-off is significantly associated with the level of son preference, slightly decreasing over time and with fertility, but it does not significantly differ by educational level of the country.     

Limit cycle oscillations of the human population

This paper investigates a mathematical model for the growth of an age-structured population. The model includes the idea (due to Easterlin) that fertility is affected by the size of the cohort in which an individual is born. It is important to note that the model investigated represents only a reasonable first step in the direction of reality from the unrealistic assumption that mortality and fertility do not change with passing time. It is shown that this general model can lead to self-excited, persistent oscillations (called limit cycles in mathematical parlance) of the birth trajectory of the population. Using data for the United States from the twentieth century, it is shown that variations in the number of births are consistent with the model discussed.     

An investigation of the timing pattern of childbearing

This paper reports an investigation of the relation between the number of live births during a woman's reproductive life-cycle and her ages at those births. Four samples of women from the United States and from the Philippines are used. The timing patterns of childbearing in these samples display several striking regularities. In all samples childbearing tends to occur in the centre of the fecund period irrespective of the number of children, so that the mean age at childbearing is essentially independent of final parity. In addition, the timing patterns are symmetric around the mean age at childbearing. Most important of all, the patterns are very alike in the different samples examined, despite large differences between average family size, methods used to regulate fertility, and economic, social, and cultural characteristics in the different populations.     

Childbearing Across Partnerships in Australia,the United States,Norway, and Sweden

This article compares mothers’ experience of having children with more than one partner in two liberal welfare regimes (the United States and Australia) and two social democratic regimes (Sweden and Norway). We use survey-based union and birth histories in Australia and the United States and data from national population registers in Norway and Sweden to estimate the likelihood of experiencing childbearing across partnerships at any point in the childbearing career. We find that births with new partners constitute a substantial proportion of all births in each country we study. Despite quite different arrangements for social welfare, the determinants of childbearing across partnerships are very similar. Women who had their first birth at a very young age or who are less well-educated are most likely to have children with different partners. The educational gradient in childbearing across partnerships is also consistently negative across countries, particularly in contrast to educational gradients in childbearing with the same partner. The risk of childbearing across partnerships increased dramatically in all countries from the 1980s to the 2000s, and educational differences also increased, again, in both liberal and social democratic welfare regimes.     

Adjusting period tempo changes with an extension of ryder’s basic translation equation

We show that the observed changes in the period tempo of fertility are biased and derive a new formula for adjusting such bias. We present illustrative applications of our proposed method to the cases of the United States and Taiwan. We then describe the relevance of adjustments of observed period fertility tempo for evaluating family planning programs aiming at delaying and reducing births to slow down population growth in developing countries. The work reported in this article also can be regarded as an extension of Ryder's basic translation equation. The extension provides a set of formulas expressing relationships of quantum-tempo between cohorts and periods under specified assumptions.     

Maybe Next Month? Temperature Shocks and Dynamic Adjustments in Birth Rates

We estimate the effects of temperature shocks on birth rates in the United States between 1931 and 2010. We find that days with a mean temperature above 80°F cause a large decline in birth rates 8 to 10 months later. Unlike prior studies, we demonstrate that the initial decline is followed by a partial rebound in births over the next few months, implying that populations mitigate some of the fertility cost by shifting conception month. This shift helps explain the observed peak in late-summer births in the United States. We also present new evidence that hot weather most likely harms fertility via reproductive health as opposed to sexual activity. Historical evidence suggests that air conditioning could be used to substantially offset the fertility costs of high temperatures.     

Recent European fertility patterns: fitting curves to 'distorted' distributions

Recent patterns of fertility in Europe show marked differences between countries. Recent United Kingdom and Irish fertility curves show 'distortions' in terms of a 'bulge' in early age fertility, distinct from the smoother curves of other European countries. These patterns may not be adequately described by mathematical functions used by previous studies to model fertility curves. A mixture model with two component distributions may be more appropriate. The suitability of the simple and mixture Hadwiger functions is examined in relation to the fertility curves of a number of European countries. While the simple Hadwiger model fits recent period age-specific fertility distributions for some countries, others which display a 'bulge' in early age fertility distributions for some countries, others which display a 'bulg' in early age fertility require a mixture Hadwiger model. Some of the parameters of the Hadwiger models appear to be related to familiar demographic indices. The simple and mixture Hadwiger models appear useful in describing and comparing fertility patterns across European countries.     

Can We Still Learn Something From the Relationship Between Fertility and Mother’s Employment? Evidence From Developing Countries

In this work, I study the impact of fertility on mothers’ employment for a sample of developing countries. Using the event of multiple births as an instrumental variable (IV) for fertility, I find that having children has a negative impact on female employment. In addition, three types of heterogeneity are found. First, the magnitude of the impact depends on the birth at which the increase in fertility takes place. Second, the types of jobs affected by a fertility shock (multiple births) are jobs identified with a higher degree of informality, such as self-employment or unpaid jobs. Finally, the heterogeneity analysis reveals that an unexpected change in fertility is stronger at a higher education level of the mother and in urban areas.     

Target Fertility,Contraception, And Aggregate Rates: Toward A Formal Synthesis

This paper develops a stock adjustment model relating total expected births to conventional aggregate fertility rates for married women over 25. Each year, cohorts bear about 20 percent of their additional expected births. Aggregate U.S. rates have been consistent with expectations as expressed in surveys between 1955 and 1975; indeed, total expected births may be inferred from aggregate fertility behavior. A peculiar empirical finding is that the additional expected fertility of nonterminators has not changed since 1955, despite the dramatic decline in total expected and actual fertility. The model leads to a dynamic expression for the duration pattern of current and cumulative fertility and for the proportion of couples who have terminated childbearing. The model is also used to analyze the effects of changing contraceptive failure rates on fertility patterns. For example, a decline in “timing” failure rates increases duration-specific fertility five years later.     

Immigration,skills and the labor market: International evidence

Using the 1994–1998 International Adult Literacy Survey, this paper compares cognitive skills and employment of immigrants in Canada, New Zealand, Switzerland, and the United States. Immigrants had lower cognitive test scores than natives in each country, with the largest gaps in the US, and small gaps in Canada and New Zealand. Male immigrants in the US were no less likely to work than natives, while in the other countries, male immigrants were less likely to be employed. Female immigrants were less likely in each country to be employed than natives, with an especially large gap for the US.The author thanks Francine D. Blau and two anonymous referees for helpful comments and suggestions and Katsuhide Yamashita for excellent research assistance. Responsible editor: Christoph M. Schmidt.     

Recent European fertility patterns: Fitting curves to ‘distorted’ distributions

Recent patterns of fertility in Europe show marked differences between countries. Recent United Kingdom and Irish fertility curves show ‘distortions’ in terms of a ‘bulge’ in early age fertility, distinct from the smoother curves of other European countries. These patterns may not be adequately described by mathematical functions used by previous studies to model fertility curves. A mixture model with two component distributions may be more appropriate. The suitability of the simple and mixture Hadwiger functions is examined in relation to the fertility curves of a number of European countries. While the simple Hadwiger model fits recent period age-specific fertility distributions for some countries, others which display a ‘bulge’ in early age fertility require a mixture Hadwiger model. Some of the parameters of the Hadwiger models appear to be related to familiar demographic indices. The simple and mixture Hadwiger models appear useful in describing and comparing fertility patterns across European countries.     

Intended and Ideal Family Size in the United States, 1970–2002

Cross‐nationally, observed fertility is well below mean levels of reported ideal family size and also usually well below survey respondents' fertility desires and intentions. The United States is an exception. In this article we: (1) discuss the importance of fertility ideals and intentions for understanding observed fertility levels, (2) propose a model that can account for variable attitude‐behavior consistency, and (3) use this model as a framework to examine trends in American women's fertility ideals, intentions, and actual fertility. Our study uses data from the General Social Surveys and the Current Population Surveys. We ask whether preferences and intentions for moderate family sizes have eroded with time. The answer is remarkably clear: the dominant American ideals and intentions are for two or three children, and these preferences have persisted across the last three decades. The unusual aggregate correspondence between fertility intentions and behavior in the United States is explained by an apparent offsetting of factors that increase/decrease fertility relative to intentions.     

The rising share of nonmarital births: Fertility choice or marriage behavior?

Much of the sharp rise in the share of nonmarital births in the United States has been attributed to changes in the fertility choices of unmarried and married women-in response, it is often argued, to public policy. In contrast, we develop and test a model that attributes the rise to changes in marriage behavior, with no necessary changes infertility. A variety of empirical tests strongly support this conclusion and invites focused attention to issues related to marriage behavior as well as to the interactions between marriage and fertility.     

Estimating birth stopping and spacing behavior

A decomposition of age-specific marital fertility rates into indices related to spacing and stopping is developed by using Coale and Trussell's indices and the first few parity progression ratios. This approach leads to estimates of the mean birth interval among low-parity births that can be used to address the issue of fertility control early in marriage. In this way the model addresses several of the most serious limitations of Coale and Trussell's approach. The usefulness of the proposed indices is demonstrated by applications to historical data from the United States and Europe.     

Do Cross-National Differences in the Costs of Children Generate Cross-National Differences in Fertility Rates?

Parity-specific probabilities of having a next birth are estimated from national fertility data and are compared with nation-specific costs of having children as measured by time-budget data, by attitude data from the International Social Survey Program, and by panel data on labor earnings and standard of living changes following a birth. We focus on five countries (the United States, the former West Germany, Denmark, Italy, and the United Kingdom), whose fertility rates span the observed fertility range in the contemporary industrialized world and whose social welfare and family policies span the conceptual space of standard welfare-state typologies. Definitive conclusions are difficult because of the multiple dimensions on which child costs can be measured, the possibility that child costs affect both the quantum and the tempo of fertility, the relatively small fertility differences across industrialized nations, and the inherent small-N problem resulting from nation-level comparisons. Empirical analysis, however, supports the assertion that institutionally driven child costs affect the fertility patterns of industrialized nations.     

Social Patterning in Body Mass Index (BMI) Among Contemporary Immigrant Groups: The Emergence of a Gradient

Although adult body mass index (BMI) displays considerable social patterning worldwide, the direction and strength of the relationship between BMI and socioeconomic status (SES) varies cross nationally. We examine social gradients in BMI for contemporary U.S. immigrants and evaluate whether their SES-BMI gradient patterns are shaped by underlying gradients in immigrant origin countries and whether they are further patterned by time in the United States. Data come from the New Immigrant Survey, the only nationally representative survey of contemporary immigrants. Results indicate that the inverse SES-BMI gradients observed among this population are strongest among women originating in highly developed countries. After arrival in the United States, however, inverse gradient patterns are driven largely by higher weights among low-SES individuals, particularly those from less-developed countries. We conclude that although certain immigrants appear to be uniquely protected from weight gain, poorer individuals from less-developed countries are doubly disadvantaged; this raises concerns about worsening inequalities in both diet and behavior between the rich and poor upon arrival to the United States.