The estimation of fertility rates from ratios of total to first births

In a previous paper a formula was derived from which the total fertility rate of a group of women could be estimated from the average number of live births to women in the reproductive period. In the present paper the argument is carried further and a method is given by which the total fertility rate may be estimated from the average number of children born to fertile women during the reproductive period. The method given in this paper may, under certain circumstances, have considerable advantages over the previous method suggested.     

Gendering fertility: Second births in Sweden and Hungary

With the growing prevalence of the dual-earner family model in industrialized countries the gendered nature of the relationship between employment and parenting has become a key issue for childbearing decisions and behavior. In such a context taking into account the societal gender structure (public policies, family-level gender relations) explicitly can enhance our understanding of contemporary fertility trends. In this paper we study the second birth, given its increasing importance in the developed world as large proportions of women remain childless or bear only one child. We focus on Sweden where gender equality is pronounced at both the societal and the family level and on Hungary where the dual-earner model has been accompanied by traditional gender relations in the home sphere. Our analysis is based on data extracted from the Swedish and Hungarian Fertility and Family Surveys of 1992/93. We use the method of hazard regression. The results suggest that the second-birth intensity increases as the combination of parenthood and labor-force attachment of either parent is facilitated. We see this in the effect of family policies in Sweden and in the higher second-birth intensity of couples who share family responsibilities as compared to those with traditional gender-role behavior in both countries. Also, the lack of any visible impact of men's educational attainment in both Sweden and Hungary is probably linked to public policies as state support for families with children has reduced the importance of income for second childbearing. A positive educational gradient for Swedish women and an essentially zero gradient in Hungary reflects the success of policy measures in reducing fertility cost for more educated women in both countries.     

A model to estimate births averted due to IUCDs and sterilizations

The computation of births averted due to a specific family planning programme requires special treatment instead of application of the usual population projection technique using conventional fertility rates. The reason for this is that adopters of a family planning method are a selective group from the general population with respect to a number of demographic and biological characteristics, including the initial susceptibility status at the time of adoption. In the present paper a matrix of annual birth probabilities specific to age at adoption of a method and duration since adoption is obtained. One matrix is presented for adopters of IUCD, another for salpingectomy, and a third for vasectomy. These matrices are used to obtain estimates of births averted for India due to IUCDs and sterilizations performed during 1956–69. The results are compared with those that could have been obtained by using the usual age-specific marital fertility rates under identical conditions, except for initial susceptibility. The entire work is programmed on a high speed electronic computer.     

On the estimation of female births missing due to prenatal sex selection

This research note is prompted by a paper by Kashyap (Is prenatal sex selection associated with lower female child mortality? Population Studies 73(1): 57–78). Kashyap’s paper, which provides 40 original estimates of missing female births, relies on an alternative definition of missing female births, leading to estimates of about half the magnitude of other estimates. There appears, therefore, a real need to take stock of the concept of missing female births widely used by statisticians around the world for assessing the demographic consequences of prenatal sex selection. This research note starts with a brief review of the history of the concept and the difference between Amartya Sen’s original method and the alternative method found elsewhere to compute missing female births. We then put forward three different arguments (deterministic and probabilistic approaches, and consistency analysis) in support of the original computation procedure based on the number of observed male births and the expected sex ratio at birth.     

The fertility effect of catastrophe: U.S. hurricane births

Anecdotal evidence has suggested increased fertility rates resulting from catastrophic events in an area. In this paper, we measure this fertility effect using storm advisory data and fertility data for the Atlantic and Gulf-coast counties of the USA. We find that low-severity storm advisories are associated with a positive and significant fertility effect and that high-severity advisories have a significant negative fertility effect. As the type of advisory goes from least severe to most severe, the fertility effect of the specific advisory type decreases monotonically from positive to negative. We also find some other interesting demographic effects.     

A model of the age patterns of births by parity in natural fertility populations

This research develops a convolution model to express the age patterns of fertility at each birth order in natural fertility populations in terms of six parameters, directly representing the proximate determinants of fertility, and a series of parity level indicators. The parity level indicators at each birth order are simply the proportions of women in a cohort who will eventually have births at each birth order it the age‐related fecundity decline is controlled. The Coale‐McNeil nuptiality model is adopted to represent the age pattern of first marriage rates and the natural fertility schedule employed in the Coale‐Trussell fertility model is incorporated to adjust age effects. The fast Fourier transform is used in solving the model numerically. It proves that the model is able to provide excellent fits to fertility for rural Chinese women in the 1950s.     

Reduction in fertility due to induced abortions: A simulation model

The impact of induced abortion on fertility under Indian conditions is studied in this paper. The model is executed on a computer. First, matrices of birth probabilities specific to age and age at marriage are obtained, with the help of a simulation model, under various assumptions regarding the incidence of induced abortion. Later, making use of these matrices, period fertility measures such as age specific marital fertility rates and crude birth rates are obtained for India for the period 1961-75. One of the findings is that the effect of induced abortion in reducing the birth rate of India will be greater if it is used as a supplement to various family planning methods.     

The use of fourier analysis to express the relation between time variations in fertility and the time sequence of births in a closed human population

A fundamental theorem of mathematical demography states that two closed populations sharing the same extended history of net fertility, no matter how variable, have the same age composition. In consequence, when in any population net fertility has long followed a purely repetitive cycle, age composition must also be repetitive with the same cycle length. Under these conditions annual births follow a path that is an exponential multiplied by a periodic time-function. If the time variation of fertility is a small amplitude sinusoidal oscillation, the periodic component of the birth sequence is also sinusoidal. The relative amplitude and timing of fertility oscillations and the consequent birth fluctuations are functions of the duration (or frequency) of the fertility cycle; the nature of the functions is determined by the age structure of net fertility.Any time sequence of fertility variation over an extended period of time can be treated as if part of a repetitious cycle of very long duration. By Fourier analysis the fertility sequence can be expressed as the sum of a series of sinusoidal terms; and finally the sinusoidal components of the resultant birth sequence can be derived. The calculated birth sequence closely approximates the actual.     

The ISEW -- not an Index of Sustainable Economic Welfare

Social Indicators Research -     

Unconditional government social cash transfer in Africa does not increase fertility

Among policymakers, a common perception surrounding the effects of cash transfer programmes, particularly unconditional programmes targeted to families with children, is that they induce increased fertility. We evaluate the Zambian Child Grant Programme, a government unconditional cash transfer targeted to families with a child under the age of 5 and examine impacts on fertility and household composition. The evaluation was a cluster randomized control trial, with data collected over 4 years from 2010 to 2014. Our results indicate that there are no programme impacts on overall fertility. Our results contribute to a small evidence base demonstrating that there are no unintended incentives related to fertility due to cash transfers.     

The value of avoided births to underdeveloped countries

Abstract An estimate of the value to a developing economy of preventing an additional birth is a useful yardstick for decisions about bonuses, information-and-dispensation campaigns, and propaganda campaigns. Enke's method of estimation incorrectly reckons private costs as public costs and attributes all the avoided consumption of the prevented child to the social account, whereas most of it would be otherwise consumed by the child's family. And at the discount rate Enke uses (15%) the effect of an added child on the marginal productivity of other workers is irrelevant. On the other hand, a 15% discount is shown to be inconsistent with other governmental decisions, and a lower discount rate reduces the value of a prevented birth in Enke's scheme. Hence Enke's method is internally inconsistent. Coale and Hoover's work on India enables one to generate an estimate for the value of an avoided birth on the basis of a complete and realistic macro-economic system. This was done by relating the differences in numbers of births in future periods (under two of the Coale-Hoover alternatives) to the differences in aggregate income that are projected (under the two alternatives). Even at the high discount rate of 15%, the value is $114. At lower discount rates the value is much higher.     

The path to lowest-low fertility in Ukraine

The phenomenon of lowest-low fertility, defined as total fertility below 1.3, is now emerging throughout Europe and is attributed by many to postponement of the initiation of childbearing. Here an investigation of the case of Ukraine, where total fertility--1.1 in 2001--is one of the world's lowest, shows that there is more than one pathway to lowest-low fertility. Although Ukraine has undergone immense political and economic transformations in the past decade, it has maintained a young age at first birth and nearly universal childbearing. Analyses of official national statistics and the Ukrainian Reproductive Health Survey show that fertility declined to very low levels without a transition to a later pattern of childbearing. Findings from focus-group interviews are used to suggest explanations of the early fertility pattern. These include the persistence of traditional norms for childbearing and the roles of men and women, concerns about medical complications and infertility at a later age, and the link between early fertility and early marriage.     

Lifetime probability of additional births by age and parity for American women, 1935–1968: A new measurement of period fertility

A new fertility measurement, probability that a woman of specified parity and age will bear a given number of births in her remaining lifetime, is proposed in this article. The measurement is a summary index of a set of age-parity-specific birth probabilities and in a particular case it is conceptually analogous to the total fertility by birth order but free from the influence of the parity distribution. Fertility of American women for the period 1935-1968 was studied by use of such lifetime probabilities. It appears that the trend of fertility of high birth orders has been parallel with that of low orders. Initiation of the recent decline in fertility depends on parity and age of woman.     

From natural fertility to family limitation: The onset of fertility transition in a sample of German villages

Utilizing data from a sample of German village genealogies, it is possible to document the changes in reproductive patterns on the family level that started to take place in Germany during the nineteenth century and formed the basis for the secular decline in fertility which eventually encompassed the entire country. One striking finding from this study was the substantial diversity among the small sample of villages in terms of the timing of the emergence of family limitation. While couples in all villages who married during the last half of the eighteenth century appeared to be characterized predominantly by natural fertility the emergence of family limitation began as early as the turn of the nineteenth century in some places and as late as the end of the nineteenth century in others. Occupational differentials with respect to family limitation were also examined. There is little evidence that changes in birth spacing played an important part in the initial phase of the fertility trnsition. Rather, the underlying process appears to involve a change from fertility patterns that were characterized by the absence of parity-dependent control to one in which attempts to terminate childbearing in response to the number of children already born becomes widespread.     

Low fertility and limited diffusion of modern contraception in Italy during the second half of the twentieth century

During the last two decades of the twentieth century, Italy, Greece, Spain, Portugal, and Japan were characterized by very low fertility levels and limited diffusion of the pill, IUD and sterilization for contraceptive purposes. This paradox is discussed for Italy by revisiting the history of contraception and reproduction during the second half of the twentieth century, and by using new data for the end of that century and the early twenty-first century. The main results are: (1) it has been possible to maintain low rates of planned and unplanned fertility without resorting to more effective contraceptive methods thanks to a careful use ofcoitus interruptus; (2) the pace of diffusion of the pill and IUD was so slow because of the opposition to contraception of the Catholic Church, a gender system emphasizing traditional male and female roles, and a medical culture that made physicians reluctant to prescribe the pill for their patients; and (3) the contraceptive patterns of Italian women born after 1960 are more similar to those of their Western counterparts, although new peculiarities appear, for example, substantial reliance on the condom by people living as couples as well as sexually active singles.