Thomas W. Pullum

A multivariate analysis of homogamy in Montevideo, Uruguay

This paper develops multivariate models to describe homogamy or, more generally, marriage preferences, for corresponding characteristics of brides and grooms. The purpose of these models is to obtain interpretable measures of the degree of homogamy (or marriage preference) on one dimension and to adjust these measures for homogamy on other dimensions. The models are applied to a sample of marriages in Montevideo, Uruguay, with pairs of corresponding variables for the brides and grooms. The analysis estimates the unadjusted and adjusted levels of homogamy on previous marital status, age, education, religion, and location. Homogamy on location, or propinquity, is the single most important variable. Previous marital status and age describe the readiness or eligibility to marry and are associated in their effect on homogamy. Education and religion describe vertical and horizontal differentiation of marriage partners, respectively. The multivariate analysis verifies that these dimensions are largely independen...

Correlations between frequencies of kin

Recent years have seen the development of formal and microsimulation models of the structure and dynamics of kin networks. These models generally assume uncorrelated fertility within and across generations. Several sets of real data, however, show positive correlations between the frequencies of various categories of kin. This paper uses formal models to calculate the correlations that will exist between certain categories of kin even if mothers and daughters have independent fertility. Mechanisms by which fertility might be transmitted from mothers to their daughters are considered and the implications for kin correlations are evaluated.

Induced abortion among unmarried women in Sichuan province, China

This report describes the social and demographic characteristics of 457 unmarried women who underwent a first trimester induced abortion at hospitals and family planning clinics in Sichuan province, China. The data show a very low level of medical complications. However, improved access to contraception for unmarried women is needed in order to reduce the incidence of unintended pregnancies and induced abortion.

Measuring Change and Continuity in Parity Distributions

Procedures are developed to allocate the change in mean fertility to the change in specific parities or groups of parities. One procedure uses the proportion at each parity and another uses parity progression ratios. Both are based on the delta method for approximating change in a function of several variables. Drawing on an analogy to survival in a life table, the relational logit model is applied to parity progression. This method allows several parity distributions to be synthesized and to have differences summarized with two parameters. The three procedures are applied to successive cohorts of white U.S. women who completed their childbearing between 1920 and 1980.

A follow-up study of first trimester induced abortions at hospitals and family planning clinics in Sichuan Province, China

Four-thousand women aged 18-40 underwent an early induced abortion at hospitals and family planning clinics in six counties in Sichuan province, China, between 1 July 1990 and 30 June 1991. The subjects were followed-up three times, on days 15, 90 and 180 after the operation. Information was obtained about their age, parity, contraceptive use, social behaviors, and gynecological and psychological characteristics before and after the abortion. The results indicate that induced abortion is safe when provided by medically trained personnel in health facilities such as hospitals or clinics. Depressive symptomatology was assessed by the CES-D and SCL-90 scales. The depressive symptoms declined over time. A substantial proportion of the abortions were to unmarried women or resulted from non-use of contraception or contraceptive failure, implying that the incidence of unintended pregnancies and induced abortions could be reduced by more effective and accessible contraception.

Adapting Fertility Exposure Analysis to the Study of Fertility Change

Fertility exposure analysis was developed recently by Hobcraft and Little in order to evaluate the relative importance of the various proximate determinants upon levels of current fertility. In the present paper we extend the analysis to the study of changes in fertility between two cross-sectional surveys. We show how to express fertility change as a product of terms which represent changes in the proximate determinants. The model of change is adapted to a log-linear framework, in which the proximate determinants on the one hand, and socio-economic variables such as education, on the other, are considered together. A few simplifications of the method are also suggested so that fewer demands are made on data. The model and its possible interpretations are illustrated with pairs of surveys from Pakistan and Mexico. In each pair, one survey was part of the WFS programme and the other was very similar but conducted five years later.

Using a modification of the capture–recapture model to estimate the need for substance abuse treatment

Abstract A Poisson regression applied the capture–recapture model to a time series of data for admissions to treatment from 1987 to 1996 to estimate the number of heroin addicts in Texas who are ‘at risk’ for treatment. A method was developed to summarize and use all of the data. The entire data set produced estimates which were lower and more plausible than those produced by drawing samples. But these better estimates were still sensitive to the assumptions of capture–recapture analysis: unique marking, independence, and consistency over time and population. The analyst must understand the local ‘drug scene’ and changes in treatment programs when making estimates.

Changes in fertility and contraception in Mexico 1977-1982.

This study was aimed at deepening understanding of the Mexican fertility transition through a comparison of data from the 1977 Mexican Fertility Survey and the 1982 National Demographic Survey. In the 5 years between surveys the total fertility rate for women ages 20-44 years dropped by 24% from 5.4 to 4.1. These reductions were relatively uniform across age groups. The most striking declines were recorded among less educated and rural women--groups that had the highest fertility in 1977 and are considered difficult to reach with family planning programs. Women with 0-3 years of education experienced a 31% decline in fertility between 1977 and 1982 compared to a 21% drop among those with 4-6 years and no change among women with 7 or more years of schooling. Moreover fertility declined by 27% among rural women compared to 20% among urban women. Overall contraceptive prevalence increased by 52% between the 2 surveys from 27% to 41%; the greatest increase (59%) was observed among women in both the 30-34 and 40-44 year age groups. Female sterilization showed the greatest growth in use (352%) in the intersurvey interval and is now the most important contraceptive method among women 30 years of age and over. Oral contraceptive use which increased by 29% remains the method of choice for women under 30 years of age. The greatest increases in contraceptive use ocurred among women at the lowest educational levels and rural women. Striking among these results are the rapidity of the fertility decline and the convergence of the reproductive behavior of different socioeconomic strata of the population. Because the decline in fertility began so soon after the official family planning program was started in 1974 it can be assumed that the demand for children in Mexico had already fallen. The impact of the program was most likely achieved through changing norms about women and the family and through reducing the costs of fertility regulation rather than any perceived increase in the costs of children.

Population Dynamics: Classical Applications of Stable Population Theory

Abstract If age-specific fertility and mortality rates are constant for a long period of time, a population will approach a fixed age distribution, and fixed overall rates, which can be calculated from the specific rates. An assumption of stability may thus enable the indirect estimation of missing data when only a few population characteristics are known. Even when the assumption is not satisfied, the stable population model provides a useful approximation to the relationships among survivorship, reproduction, and age structure. Several applications are provided, ranging from the simple exponential model of population growth to models that estimate numbers of kin.