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N B Ryder

Publications and source records attributed to N B Ryder.

At least 19 recordsLinked to original sources

A time series of instrumental fertility variables.

Temporal variations in conventional fertility measures reflect the operation of instrumental variables: quantitative and temporal intentions; success in achieving intentions; and reproductive conditions. A set of such variables is described, using data from the 1975 National Fertility Study. There was a large decline in the number of intended conceptions, a recent large rise in the extent of their delay, a very large decline in rates of failure to delay or terminate fertility, and a very large recent rise in sterilization. But one problem proved important and intractable: When the data source is a cross-sectional survey, the length of open interval is inherently different for real and for synthetic cohorts, it is strongly related to reproductive intention, and that affects the classification of exposure to risk in the open interval.

Data Collection

A model of fertility by planning status.

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.

Birth Rate

The predictive validity of reproductive intentions.

On the basis of data collected in the 1975 National Fertility Study (NFS) in which continuously married white women interviewed in the 1970 NFS were reinterviewed five years later, the aggregate and individual validity of reported fertility intentions is evaluated. The main finding about aggregate prediction is that 1970 intentions overestimated 1971-1975 fertility to the same extent as the conventional 1970 total fertility rate. The conclusion is that intentions suffer all of the same vulnerabilities as other period measures. At the individual level, the validity of intentions is considerable in comparison with most other indicators.

Adult

The predictability of fertility planning status.

For any couple, the planning status of a pregnancy (what they intended, whether they used contraception, and whether they were successful) is strongly dependent on the planning status of their preceding pregnancy. The introduction of more acceptable and effective methods of fertility regulation has, however, attenuated the strength of these relationships. The patterns of continuity and change in planning status from pregnancy to pregnancy provide a parsimonious description of reproductive behavior over the course of the life cycle and of the major trends in planning in the recent past.

Contraception

Use of oral contraception in the United States, 1965. In only 5 years oral contraception has become a major means of regulating fertility.

This is the first report from the Na-tional Fertility Study, 1965, a survey of the reproductive behavior of a national sample of married women, under the age of 55, living with their husbands. The report presents basic data on the use of oral contraception by women under the age of 45, in relation to age, parity, education, race, and religion. The study leads to certain conclusions, as follows. Present, past, and prospective use vary inversely with the age of the woman and directly with the number of years of schooling; the majority of young women with college training have already used the oral contraceptive. Use by Negroes is somewhat less extensive than use by whites, particularly for ages below 25; some of this difference is explainable by concomitant racial differences in educational level. Negroes seem less likely than whites to use oral contraception for timing early births, and more likely, when they do use it, to be attempting to terminate their fertility. The same observation holds for white Catholics in relation to white non-Catholics. Although the extent of use may be lower among Catholics than non-Catholics, the proportion of Catholics who report use is substantial indeed in view of the persisting theological controversy. The prospects for increased use of oral contraception seem very good at present, but they may be limited by further developments in the technology of fertility regulation. Meanwhile the birth rate has declined substantially. Although much sophisticated analysis of other data from the survey will be required to determine the extent of the contribution of oral contraception to this decline, the findings presented here suggest that the contribution is substantial for young married couples. The major effect on the couple's eventual number of children may be less than the effect on the time pattern of childbearing; in any event, both lower eventual parity and delayed fertility contribute to a decline in the numbers of births from year to year. Whatever the intent may be, it is apparent that young American couples have adopted a new means for achieving their reproductive goals.

Adolescent

The specification of fertility planning status.

The principal obstacle to accurate measurement of fertility planning intentions in cross-sectional surveys is the disposition of the respondent to provide the interviewer with a reconstruction of the couple's history which departs more or less from what actually happened... Since married couples in America are now close to effective planning of fertility, the future of reproduction in the United States will depend much more than in the past on reproductive intentions. From this viewpoint, the uncertainty of reproductive intentions as shown here suggests extreme circumspection in using current reproductive orientations for future projections.

Abortion, Legal