A modified hurdle model for completed fertility

In this paper it is argued that models for completed fertility have to take into consideration that childless couples and couples with an only child are qualitatively different from couples with two or more children. Indeed, these differences may be the cause of the underdispersion that characterizes completed fertility data. An empirical illustration using Portuguese data suggests that accounting for the qualitative difference between having zero, one, or more children leads to considerable improvements over a model of the type generally used to describe this sort of data.     

On the distribution of completed parities when fertility is heritable

Over the last one hundred years, there has been, in many developed countries, a demographic convergence towards the two child family. The possible implications for population growth of such a tendency are considered in this paper in terms of both family limitation and also the intergenerational transmission of fertility. These two effects interact so that as the proportion of two‐child families increases, the possible influence of mother‐daughter fertility associations on population growth decreases, though even now it could override otherwise significant changes in either or both of the birth and death intensities. In particular, it is shown that according as to how fertility is transmitted through generations, it is still possible to have zero growth rates consistently with a widely dispersed stable distribution of family size as well as a typical mortality regime.     

On the distribution of completed parities when fertility is heritable

"Over the last one hundred years, there has been, in many developed countries, a demographic convergence towards the two child family. The possible implications for population growth of such a tendency are considered in this paper in terms of both family limitation and also the intergenerational transmission of fertility. These two effects interact so that as the proportion of two-child families increases, the possible influence of mother-daughter fertility associations on population growth decreases, though even now it could override otherwise significant changes in either or both of the birth and death intensities. In particular, it is shown that according...to how fertility is transmitted through generations, it is still possible to have zero growth rates consistently with a widely dispersed stable distribution of family size as well as a typical mortality regime." (SUMMARY IN FRE)     

The prediction of fertility among catholics: A longitudinal analysis

A longitudinal analysis of the reproductive behavior of a sample of Catholics who were participants in the 1965 NFS and reinterviewed in 1969 is reported in this paper. Fertility over the period studied varied systematically with the additional number of children intended in 1965. In addition, this study has documented a predictive role for method of contraception and the experience of premarital pregnancy. Women using less effective methods and those premaritally pregnant had higher fertility over the interval net of controls for other variables in the analysis, including life-cycle stage and 1965 intentions. Surprisingly, the planning status of the last pregnancy before 1965 was not found to have any independent association with subsequent fertility.     

The fertility of two-generation urbanites

In this paper it is argued that in studies of urban fertility, the relationship between socio-economic variables and fertility has been obscured by the presence of rural migrants in the populations under investigation. Accordingly, data obtained from families of completed fertility in six probability samples of metropolitan Detroit are divided into two groups, farm migrants and two-generation urbanites.

In general, the socio-economic differences in fertility observed among the “pure” urban types in Detroit are found to be small and inconsistent, most of them being statistically insignificant. The inverse fertility pattern found in the total Detroit population is attributed to : (a) the overrepresentation of farm migrants (who have high fertility) in the lowest social and economic positions in the city, and (b) the pronounced inverse pattern of fertility among the farm migrants.

It is suggested that the absence of an inverse fertility pattern among twogeneration urbanites and its presence among the farm migrants can be attributed to differences in family organization.     

The Pattern of Age-Specific fertility rates

A study of the pattern of age-specific fertility rates by five-year age-groups has revealed the possibility of using the Pearsonian type I curve as a graduating equation. Such distinctions have been examined for fifty countries having high, medium, and low fertility rates. Results have been found to be quite satisfactory, even when, for purposes of simplicity, the parameters have been restricted to depend on the first two moments, instead of the first four. The number of independent parameters has thus been reduced to only three, and method shave been suggested for their estimates, using ancillary information which is usually provided in the census reports. The findings seem to be particularly useful for countries lacking effective registration systems of vital events such as births related, as they are, to the age of the mother.In short, the determination of a series of age-specific fertility rates depends primarily on the modal fertile age (a1) and on one of the two exponents (m, or m2) of the type I distribution. It has been shown that the proportions of women married in the age groups 20-24 years and 25-29 years can be used for approximate evaluations of both of these parameters. While estimates of a, and m, are sufficient to generate a relative distribution of age-specific fertility rates, actual values can be obtained if, in addition, the annual number of births is either known or can be estimated from census age distributions of children.Modal distributions of relative values of age-specific fertility rates (such that the sum of these rates adds up to 100.0) have also been obtained for different combinations of al and m1, but are not shown here for lack of space. Once the estimates of al and m, have been made, the modal tables can always be referred to for the corresponding distributions of age-specific fertility rates.     

The changing fertility of the Japanese

The Japan of the middle of the nineteenth century was a backward agrarian state of perhaps 35 million people. Three-quarters of a century later, the 75 million people of an industrialized and urbanized Japan had challenged the industrial and military power of the West itself in a daring attempt to achieve economic and political control over eastern Asia and the islands of Oceania. Population growth had stimulated economic and political expansion, but in 1940 when the Planning Board of the Cabinet reported to the Imperial Japanese Government that the country would need perhaps 200 million people to maintain the hegemony of the East, population growth was already slowing. Japanese projections of the trends of the interwar period indicated that the maximum population would be reached by the end of the twentieth century, and that it would be slightly less than 125 million.²     

The effect of income on fertility

Abstract Cross-sectional data and long-period time series data have generally shown an inverse relationship between income and fertility. But short-period time series data over the business cycle have shown a direct relationship. The first part of this paper resolves this apparent paradox by showing that it arises from a statistical illusion-specification bias due to omitted lagged variables. The second part of the paper then considers the likely unconditional effect of income on fertility in several sorts of situations: (a) secular income increase in less developed countries; (b) cyclical income change in industrialized countries; (c) secular income increase in industrialized countries; and (d) incentive payments for higher and lower fertility.     

The pattern of puerto rican fertility

The vital statistics of Puerto Rico for the period 1943–8 reveal a continuation of high crude birth rates and age-specific fertility rates. A careful examination of the figures does not suggest that there is as yet any decline in fertility, though with increasing urbanization such a decline may be expected to take place in the not too distant future.     

The influence of first generation fertility and economic status on second generation fertility

This paper examines the impact of parental economic status and family size on the actual and expected fertility of adult children using longitudinal data from two generations of families participating in the Panel Study of Income Dynamics. There was a modest positive relationship between first generation family size and second generation fertility. More importantly, the ideal family size of the parental family was more closely related to fertility behavior and plans in the second generation than was actual parental family size. In addition, the data revealed the hypothesized negative correlation between parental financial status and second generation fertility behavior and plans. Several mechanisms which could produce the correlation between parental characteristics and the fertility of their children are explored.The analysis reported in this paper was supported by Contract NO1-HD-42856 from the National Institute for Child Health and Human Development, Center for Population Research. Dr. Thornton is affiliated with the Survey Research Center, Institute for Social Research, University of Michigan, Ann Arbor, MI 48106. Requests for reprints should be directed to him.     

A probability mixture model of completed parity

This research was designed to find a probability model that would adequately describe completed parity for women in populations characterized by high fertility combined with high zero parity. A negative binomial mixture distribution was adapted for this purpose. The form of this distribution suggests the hypothesis that human populations consist of two subgroups of women with respect to completed parity, defined according to whether they do or do not produce viable offspring. Results of the present research further suggest that the proposed distribution for completed parity has general applicability across human populations, whether they are of a high or low fertility type, and whether they have a high or low zero parity.     

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.     

The Decline of marital fertility in Japan

Summary Studies concerning the demographic history of Tokuwara and Meiji Japan suggest that fertility rose substantially before declining during the twentieth century. Were the motivations and circumstances which held down natality during the feudal period similar to those which account for the modern fertility decline and the low birth rate obtaining in the Japan of to-day? The thesis of this paper is that the pre-modern situation was fundamentally different from the modern one. During the Tokugawa era infanticide and abortion were used, independently of parity, to eliminate weak offspring whose chances of survival were deemed poor. Desired natality generally exceeded natural fertility. With the rise of income per head during the Meiji period the population's need for these desparate practices vanished. To-day parity-specific control characterizes fertility. Parityspecific control was diffused throughout Japan in response to declining desired fertility. Desired fertility fell significantly below natural fertility sometime during the late nineteenth or early twentieth century and the wish to reduce actual fertility to the desired level stimulated the adoption of parity-specific control. The speed of decline in marital fertility was partially governed by official policies toward contraception and abortion, contraception and abortion.     

The end of “Catholic” fertility

Catholic and non-Catholic fertility during the post-World War II period are compared in this paper. Evidence accumulated across five sample surveys of fertility in the United States, which were conducted at five-year intervals from 1955 through 1975, forms the basis for the analysis; both cohort and period measures are employed. Starting from a situation where Catholic fertility was very little higher than that of non-Catholics, it is shown that the differential increased markedly during the baby boom and then declined to a point where the two trends nearly come together in the mid-1970s. Interpretation of the recent convergence in the light of various theories that have been put forward to explain the differential suggests that it will be an enduring phenomenon.     

The effect of normative pressures on fertility

Using longitudinal data from a sample of urban, white, married U.S. couples, this paper shows the effects of normative pressures from family and friends on whether or not the couple had a pregnancy within one year. A comparison of parity-specific and all-parity models indicates that more information and better predictions can be obtained from parity-specific models. Normative pressures predict pregnancy best at zero parity, with progressively attenuated predictions at higher parity. A comparison of models using husband and wife data together shows that two-sex models are better than models using either sex alone. In a variety of different models, normative pressures reported by husbands are better predictors of pregnancy than are normative pressures reported by wives. A comparison of models using aggregated measures of normative pressures with models identifying the separate individual sources of pressures indicates that each treatment provides different insights into the effects of normative pressures, but that predictive power is lost through aggregation.This study was supported by a grant from the Center for Population Research, NICHD (Grant No. N01-HD-42804). Boone Turchi and Karl Bauman were collaborators on the original study. The authors would like to thank Judy Kovenock for data analysis. Requests for reprints should be directed to J. Richard Udry, Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514.     

The fertility transition around the world

In this paper, we study the evolution of the distribution of fertility rates across the world from 1950 to 2005 using parametric mixture models. We demonstrate the existence of twin peaks and the division of the world’s countries in two distinct components: a high-fertility regime and a low-fertility regime. Whereas the significance of twin peaks vanishes over time, the two fertility regimes continue to exists over the whole observation period. In 1950, about two thirds of the world’s countries belonged to the high-fertility regime and the rest constituted the low-fertility regime. By the year 2005, this picture has reversed. Within both the low- and the high-fertility regime, the average fertility rate declined, with a larger absolute decline within the high-fertility regime. Visually, the two peaks moved closer together. For the low-fertility regime, we find both β- and σ -convergence but we cannot establish any convergence pattern for the high-fertility regime. Our results support the idea of conditional convergence where the condition is the successful initiation of the fertility transition. The results are less supportive of the existence of a unique high-fertility equilibrium.     

Analysis of completed parity using microsimulation modeling

"This paper aims to construct a demographic microsimulation model, which is easily applicable to gene transmission..., and to examine the distribution of completed parity as a fertility measure at a population level according to the schedule of individual life course....The simulation model was applied to the data of the Gidra-speaking people living in the lowlands of Papua New Guinea."     

The fertility of teachers in England and Wales

Data on the fertility of teachers in grant earning schools in England and Wales were collected in 1955 as part of a general survey into the social characteristics of teachers. The survey was financed by the Nuffield Foundation with a contribution from the Population Investigation Committee. A subsequent article will discuss some possible determinants of fertility and in particular the interrelationship between social mobility and fertility. The present note describes changes in cohort fertility of teachers since 1915 and compares average family size with that of other sections of the population. The average number of children per married male teacher declined from 1.81 for the pre-1920 cohort to 1.47 for 1930–34. Segmental data after 1935 indicate a rise to approximately 2 children per family. Comparison with the Family Census suggests that the number of children of teachers is between 10% and 20% below that of all professions combined when the age at marriage of the wife is taken into account.     

The determinants of early fertility decline in Texas

This study examines the determinants of fertility control in a frontier population made up largely of German-Americans during the years from 1850 to 1910. The analysis employs a complex register of population constructed from census enumerations, civil and ecclesiastical vital registration, and tax assessment rolls. The article begins with a series of bivariate analyses with cohort of mother’s birth, religion, ethnicity, and husband’s occupation determining marital fertility. The second half of the paper presents a multivariate model of the determinants of fertility using these and other demographic characteristics as independent variables. The conclusions emphasize the importance of the overall trend toward fertility decline in the United States, as well as the role of religion and of occupational differences, in determining changes in fertility behavior in the population of Gillespie County, Texas.