Use of a fertility simulation model to refine measurement techniques

A stochastic model involving the recurrent events (births, foetal deaths, etc.) associated with human reproduction is defined. Its simulation by means of a Monte Carlo program is described. The model is used to investigate the role of chance in producing biases in certain demographic measurements, particularly as regards the estimation of sterility, foetal death and stillbirth ratios, and birth intervals.     

The project coordinator's problem

A project coordinator has a set of activities with known durations and values which are available for scheduling within a given horizon. There may be both precedence and corequisite restrictions (two activities are corequisites if scheduling one implies the other must be scheduled). The project coordinator's problem is to select the activities to be scheduled, and their start times, so as to maximize the net value of the project when there is no penalty for failing to schedule an activity. An efficient solution procedure is developed and illustrated and several generalizations are discussed.     

The Impact of Childhood Sexual Abuse and Other Forms of Childhood Adversity on Adulthood Parenting

This study investigated the independent impact of child sexual abuse on five dimensions of adulthood parenting after controlling for other forms of childhood adversity in a predominantly African-American sample of mothers receiving public assistance (N = 483). An analysis of data previously collected as part of the Illinois Families Study Child Well-Being Supplement was conducted to address these questions. Data were analyzed using hierarchal multiple regression. Childhood sexual abuse survivors reported significantly lower rates of parental warmth, higher rates of psychological aggression, and more frequent use of corporal punishment than mothers who had not experienced childhood sexual abuse. These effects, however, were nonsignificant when sociodemographic factors and other forms of childhood adversity were considered. Implications for future research are provided.     

Photo‐documenting the needle exchange: methods and ethics

When research subjects are people with stigmatized identities, then special consideration must be given to their desire for privacy and anonymity. This is especially true when photographs constitute the recorded data. This paper discusses some challenges in conducting research in a needle exchange located in a small city. Within the needle exchange, the camera posed a threat to drug users who preferred to remain anonymous, if not invisible. Ethical considerations and emotional frustration, stemming from the need and desire to get photographs of clients while respecting their obvious desire for privacy, are discussed. The practical difficulties associated with getting photographs and some methods for facilitating interaction with clients are also presented.     

Explaining age differences in women’s emotional well-being: The role of subjective experiences of aging

ABSTRACT

Our study examines explanations for the “paradox” of older women’s better emotional well-being compared with younger women. We consider the role of subjective experiences of aging in a society that devalues older women. Using a sample of women (n = 872) from the National Survey of Midlife Development in the United States (1995–1996 and 2004–2006), we examine the role of five components of the subjective experience of aging in explaining older women’s better emotional well-being compared with younger women: age identity, conceptions of the timing of middle age, aging attitudes, aging anxieties, and self-assessed physiological changes. We find that, compared with women 50–54 years old, those 35–39 years old report lower positive affect, and those 25–49 report higher negative affect. These patterns are partially explained by younger women’s greater anxiety about declines in health and attractiveness and older women’s more youthful identities. Our study underscores the value of considering the implications of our ageist and sexist society for women’s emotional well-being across adulthood.     

Effects of various factors on selection for family planning status and natural fecundability: A simulation study

The effect of various factors on selection for family planning status and for natural fecund ability is studied in a simulation that incorporates a beta distribution of fecundability among women. The mean fecundabilities of current spacers, current limiters, current nonusers, and pregnant women are compared. These ratios are influenced by duration of marriage and by desired number of children. Effects of different levels of contraception are measured. Another strategy, spacing the last two wanted births, is also studied. It is found that breast-feeding status has little effect on fecundability selection. The women usually found to have greatest fecundability are not those recently pregnant at durations of marriage five and ten years, unless they wanted fewer than two children, but rather those who are using contraception to limit the number of children.     

Risk-taking behavior in the presence of nonconvex asset dynamics

The growing literature on poverty traps emphasizes the links between multiple equilibria and risk avoidance. However, multiple equilibria may also foster risk-taking behavior by some poor people. We illustrate this idea with a simple analytical model in which people with different wealth and ability endowments make investment and risky activity choices in the presence of known nonconvex asset dynamics. This model underscores a crucial distinction between familiar static concepts of risk aversion and forward-looking dynamic risk responses to nonconvex asset dynamics. Even when unobservable preferences exhibit decreasing absolute risk aversion, observed behavior may suggest that risk aversion actually increases with wealth near perceived dynamic asset thresholds. Although high ability individuals are not immune from poverty traps, they can leverage their capital endowments more effectively than lower ability types and are therefore less likely to take seemingly excessive risks. In general, linkages between behavioral responses and wealth dynamics often seem to run in both directions. Both theoretical and empirical poverty trap research could benefit from making this two-way linkage more explicit.     

Computation of determinantal subset influence in regression

One of the important goals of regression diagnostics is the detection of cases or groups of cases which have an inordinate impact on the regression results. Such observations are generally described as influential. A number of influence measures have been proposed, each focusing on a different aspect of the regression. For single cases, these measures are relatively simple and inexpensive to calculate. However, the detection of multiple-case or joint influence is more difficult on two counts. First, calculation of influence for a single subset is more involved than for an individual case, and second, the sheer number of subsets of cases makes the computation overwhelming for all but the smallest data sets.Barrett and Gray (1992) described methods for efficiently examining subset influence for those measures that can be expressed as the trace of a product of positive semidefinite (psd) matrices. There are, however, other popular measures that do not take this form, but rather are expressible as the ratio of determinants of psd matrices. This article focuses on reducing the computation for the determinantal ratio measures by making use of upper and lower bounds on the influence to limit the number of subsets for which the actual influence must be explicitly determined.