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Censuses and surveys frequently collect information on period fertility through questions on the timing of last births. The standard approach to estimating fertility with open-interval data uses the proportion of women giving birth in the year before the interview. I propose a more efficient, maximum likelihood method for estimating fertility from open-interval data. I illustrate a mathematical derivation of the new method, perform sensitivity analyses, and conduct empirical tests with Brazilian census data. The new estimators have small biases and lower variance than standard estimators for open-interval data. Consequently, the new method is more likely to generate accurate results from small or moderately sized samples. [ABSTRACT FROM AUTHOR]

A summary of 298 male and 358 female respondents in the Lae urban area of Papua New Guinea in 1981 revealed a relatively high level of contraceptive awareness, but the level of contraceptive use is low. However, the overall current usages of non-traditional methods for the wives of the male and for the female respondents are 34–2% and 37% respectively. The male and the female respondents have the same views on the ideal family size—approximately three children. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM AUTHOR]

This article presents the author's comment on the paper "Starting, Stopping, and Spacing During the Early Stages of Fertility Transition," by J. Knodel. Knodel's article is one of a number of recent studies to address more precisely the behavioral changes that accompanied historical fertility declines. One of the central questions in this discussion has been the relative importance of two alternative, and perhaps complimentary, fertility-limiting behaviors. The first of these behaviors, stopping, refers to the attempted truncation or termination of childbearing after some desired family size has been achieved. A second behavior that may be used to limit achieved fertility is the intentional lengthening of interbirth intervals or delay during marital childbearing, that is, spacing. In at least some fertility declines, lengthened interbirth intervals appear to have been significant. Knodel employed age at last birth as an indicator of stopping behavior, but he also noted that increases in interconfinement intervals may be anticipated to increase open intervals and thereby lower the age at last birth.

This paper addresses the issue of the relationship of fertility between successive generations over the course of a 19th-century frontier fertility transition. Intergenerational event histories are used to explore the relationships between mothers' and daughters' completed family size. Results suggest that daughters' fertility levels are responsive to their mothers' relative fertility and age at marriage (as compared with mother's contemporaries). Effects of exposure to a number of younger siblings, controlling for cohort biases, are also examined. A multivariate proportional hazard analysis of daughter's age at marriage and parity-specific birth intervals demonstrates the direct and indirect effects of intergenerational fertility associations on fertility timing. [ABSTRACT FROM AUTHOR]

Our analysis of changing birth interval distributions over the course of a fertility transition from natural to controlled fertility has examined three closely related propositions. First, within both natural fertility populations (identified at the aggregate level) and cohorts following the onset of fertility limitation, we hypothesized that substantial groups of women with long birth intervals across the individually specified childbearing careers could be identified. That is, even during periods when fertility behavior at the aggregate level is consistent with a natural fertility regime, birth intervals at all parities are inversely related to completed family size. Our tabular analysis enables us to conclude that birth spacing patterns are parity dependent; there is stability in CEB-parity specific mean and birth interval variance over the entire transition. Our evidence does not suggest that the early group of women limiting and spacing births was marked by infecundity. Secondly, the transition appears to be associated with an increasingly larger proportion of women shifting to the same spacing schedules associated with smaller families in earlier cohorts. Thirdly, variations in birth spacing by age of marriage indicate that changes in birth intervals over time are at least indirectly associated with age of marriage, indicating an additional compositional effect. The evidence we have presented on spacing behavior does not negate the argument that parity-dependent stopping behavior was a powerful factor in the fertility transition. Our data also provide evidence of attempts to truncate child- bearing. Specifically, the smaller the completed family size, the longer the ultimate birth interval; and ultimate birth intervals increase across cohorts controlling CEB and parity. But spacing appears to represent an additional strategy of fertility limitation. Thus, it may be necessary to distinguish spacing and stopping behavior if one wishes to clarify behavioral patterns within a population (Edlefsen, 1981; Friedlander et al., 1980; Rodriguez and Hobcraft, 1980). Because fertility transition theories imply increased attempts to limit family sizes, it is important to examine differential behavior within subgroups achieving different family sizes. It is this level of analysis which we have attempted to achieve in utilizing parity-specific birth intervals controlled by children ever born. First, our analysis of all birth intervals for a series of cohorts, across the fertility transition, controlling for CEB, suggests that even during the periods of natural fertility, there were, at least among our population, a group of women who both spaced and limited the number of children ever born. Over the course of the transition, because increasing numbers of women modify their behavior to terminate childbearing at lower levels of children ever born, they appear to adopt a pattern of birth spacing already evident among a small group of women in earlier, seemingly natural fertility birth cohorts. Our discussion has also identified several difficulties or compositional effects which may arise in computing simple averages of birth intervals as indicators of the relevant extent of spacing and stopping behaviors. This study was designed also to determine whether the transition within our study population was principally the result of women adopting birth spacing schedules already extant within sub- groups of the population or the product of fertility limitation late in the childbearing career. Our data indicate that birth intervals for the population as a whole increase following the early period of natural fertility. These conclusions are consistent with earlier maórosimulation studies (Anderton et al., 1982; Willigan et al., 1982) in which it was found that a hypothetical simulation model fits observed data only when the model specified a set of increasing birth intervals spread across a considerable range of parities for women of any given completed family size. Accompanying, and abetting, this change in fertility behavior was a shift to older ages of marriage characterized by longer birth intervals. There are, of course, practical issues to be addressed if one is to accept the argument that spacing was involved in limiting fertility, and that the fertility transition involved a compositional shift from subcohorts with short intervals to subcohorts with long birth intervals. First, there is substantial evidence from historical demographic research that the fertility transition is marked primarily by parity dependent control, reduced age at last birth and lengthened penultimate and ultimate birth intervals. Such conclusions are also supported by evidence from a number of family planning pro- grams in developing societies with high fertility. Specifically, adoption of contraception is most frequent among high parity, older women. We do not dispute these findings. We do, however, suggest they may be incomplete. Large samples of historical populations which make it possible to disaggregate populations over the course of the entire transition by CEB and parity provide additional information. A second practical issue is whether the means to space systematically and there-by to limit family size were available prior to the introduction of modern contraceptive technology. Prior to the time studied in this paper, and in the absence of modern contraceptive technology, women in France reduced family size substantially. Fertility had also declined significantly among the populations of the Eastern sections of the United States from which the original members of the LDS Church, heavily represented in our sample, had been recruited. It seems, therefore, that modern contraceptive technology is not a necessary condition for family limitation. The results of this analysis have implications for both historical demographic research and contemporary family planning policies. We have clearly supported previous authors' suggestions that birth interval analyses provide valuable in- sights to behavioral change and supplement other fertility indices in historical demographic research. The combined evidence of increasingly long birth intervals over cohorts and the presence of individuals demonstrating such behavior during the "natural" fertility period suggest adaptive fertility behavior rather than innovative behavior underlying the fertility transition within this population. In turn, our analysis suggests that further study of birth intervals and the spread of fertility limitation may be relevant to contemporary settings. [ABSTRACT FROM AUTHOR]

Contemporary populations frequently space the births of children, and also attempt to stop childbearing after achieving a desired family size. While stopping behavior was evident in European populations in the late nineteenth century, little is known about the degree to which they attempted to space their children at specific interval lengths. This paper compares spacing patterns among various groups of white U.S. women in 1900, who were distinguished by varying family sizes and levels of fertility control. On the whole, there is little evidence of childspacing differences among native white populations, except for some very low parity women. The findings support the continued analysis of age patterns of fertility as the major means for determining the onset of conscious family limitation. [ABSTRACT FROM AUTHOR]

The impact of female employment on fertility preferences and behavior is examined with data from a 1980 national sample of Taiwanese women. The guiding hypothesis is that the greater the involvement of women in the impersonal market sector, the lower the fertility preferences, the longer the first birth interval, and the lower the actual fertility. Findings reveal that female employment in Taiwan is only weakly related to reproductive behavior. Even with increased participation of women in the modern market sector, female employment apparently has little impact on fertility preferences or behavior. Implications are drawn for policies aimed at lowering fertility. [ABSTRACT FROM AUTHOR]

Recognizing that postwar trends in family size derive both from changes in the living arrangements of adults and from changes in the presence of children, this paper develops annual estimates of mean family size, mean members less than 18, and mean members 18 and older by race, by family type, and by age of head. Group differences in the course and source of changes in family size are evident as anticipated on the basis of group differences in family structure, economic resources and life cycle stage. [ABSTRACT FROM AUTHOR]

This paper presents some main results of an investigation by life table methods of birth interval data in cohabitational unions (marriages as well as consensual unions) in current Danish cohorts. Our results confirm previous findings that an early age at the start of recorded exposure to childbearing risk is indicative of a rapid pace and high level of subsequent fertility. The analysis modifies previous results and adds several new details regarding cohort trends and the effect of parity at the start of reported cohabitation. For each parity within a period of cohabitation, fertility differentials by reported starting age seem to have diminished from our older cohorts (of age up to 49 years in 1975) to our younger ones (of age less than 30 years in 1975). There are indications of a dramatic change in childbearing behaviour following the arrival of novel attitudes to non-marital cohabitation and childbearing in Denmark about 1967. [ABSTRACT FROM AUTHOR]

Utilizing panel data on families, estimates are made of the effects of children on asset accumulation, asset composition, consumption, and family income. Young children are found to depress savings for young families but to increase savings for marriages of duration greater than five years. The principal channel through which children act to reduce savings is the decline in female earnings associated with the child-induced withdrawal of wives from the labor force. Family consumption actually decreases with the birth of a child, but this reduction is insufficient, for young families, to offset the fall in income. For families in which the wife does not work the estimates suggest that savings may actually increase with children. [ABSTRACT FROM AUTHOR]

Data from the 1965 and 1970 National Fertility Studies are used to produce classifications of births and exposure to births by planning status for real and synthetic marriage cohorts, covering the experience of the 1940s, 1950s, and 1960s. Indices of reproductive input (three ends, three means, and three conditions) and of conventional reproductive output (such as the mean number of unintended births) are derived from these observations. The outputs are expressed as deterministic equations in terms of the inputs; this permits the study of the structure of fertility determination. The model provides a parsimonious description of the sources of change in fertility and an instrument of possible use in policy. [ABSTRACT FROM AUTHOR]

Using the 1970 1/1,000 Public Use Sample of the U.S. population, the relationships of the closed and open birth intervals with parity and mother's age, with parity and marital duration, and with children ever born/marital duration and mother's age are analyzed. These findings both replicate and expand on Srinivasan's earlier research on the open interval. The open interval is more sensitive as an index of marital fertility when marital duration and parity are controlled than when mother's age and parity are controlled. [ABSTRACT FROM AUTHOR]