Smoothing a Time Series by Segments of the Data Range

We consider the problem of estimating a trend with different amounts of smoothness for segments of a time series subjected to different variability regimes. We propose using an unobserved components model to consider the existence of at least two data segments. We first fix some desired percentages of smoothness for the trend segments and deduce the corresponding smoothing parameters involved. Once the size of each segment is chosen, the smoothing formulas here derived produce trend estimates for all segments with the desired smoothness as well as their corresponding estimated variances. Empirical examples from demography and economics illustrate our proposal.     

Commercial sex between men: A prospective diary‐based study

This paper describes the results of a self‐reporting dairy completed by 186 male sex workers (MSWs) over a 2‐week period in Brisbane, Sydney, and Melbourne, Australia. The diary was completed following each commercial sex encounter by the MSW. The results reveal that MSWs reported 2088 commercial sex encounters during the study period, with an average of 11.2 encounters per MSW. The majority of sex encounters took place in either the client's or the MSW's residence, with significant variations by city. The average sexual encounter lasted 70 minutes, and comprised two sexual acts, masturbation and oral sex. Condom use was reported in 67.4% of all the encounters. Using the AIDS Council safe‐sex classification system, the majority of the commercial sex encounters fell in the “safer sex” category; however, there were significant differences by source of clients and place of the encounter. Use of drugs and alcohol reveal interesting patterns: Clients were more likely to use alcohol, while MSWs had significant differences of usage of the different drugs. This study demonstrates that the majority of MSWs are offering and practicing safe sex behaviours, however, MSWs working in the street setting are still likely to be practising unsafe sex. Male sex work is becoming an organised business and this provides opportunities to implement further public health interventions.     

A class of semiparametric transormation frailty models with application to estimating treatment effects and heterogenity in aids clinical traials

Muitivariate failure time data are common in medical research; com¬monly used statistical models for such correlated failure-time data include frailty and marginal models. Both types of models most often assume pro¬portional hazards (Cox, 1972); but the Cox model may not fit the data well This article presents a class of linear transformation frailty models that in¬cludes, as a special case, the proportional hazards model with frailty. We then propose approximate procedures to derive the best linear unbiased es¬timates and predictors of the regression parameters and frailties. We apply the proposed methods to analyze results of a clinical trial of different dose levels of didansine (ddl) among HIV-infected patients who were intolerant of zidovudine (ZDV). These methods yield estimates of treatment effects and of frailties corresponding to patient groups defined by clinical history prior to entry into the trial.     

Introduction Are We Ready to Translate Research Into Programs?

There is enough basic research on social cognition, developmental psychology,and peer relations as they relate to prejudice, discrimination, and stereotyping to address program development and evaluation. At the same time, there are enough race relations programs being developed and implemented to inform basic research on prejudice. This issue brings together articles on the interface between basic research and programs on prejudice. The articles focus onspecific programs such as affirmative action, multicultural and bilingual education, cooperative learning, social-cognitive skills training, and bystander interventions. This introductory article provides an overview of the goals and implications of the issue.     

The market for (Ir)reproducible econometrics

Context: As the volume and complexity of research have increased, the amount of time spent on Institutional Review Board (IRB) review has decreased. The complexity of research has expanded, requiring increasingly specialized knowledge to review it. Dilemma: Under the current system, increasing numbers of research studies requiring expertise in ethics, new technologies or diverse study designs place a substantial burden upon local IRBs and often result in substantial variability among their reviews. This lack of uniformity in the review process creates uneven human subjects’ protection thus undermining the intent of the Common Rule. Objectives: To outline a scenario for expert centralized IRB review via implementation of a national virtual IRB review system overseen by the Office for Human Research Protections (OHRP). Conclusions: The complicated ethical issues and science involved in much of current research warrant an expert review panel. Centralized review would enable expert review specific to the research at hand, ensure consistency in human subjects protection, reduce the burden on local IRBs, and may reduce time spent obtaining approval. A centralized virtual system would allow IRB members to remain at their institutions while providing unprecedented expert review through currently available technology, and make information regarding monitoring and adverse event reporting available online in real-time.     

Development and Consideration of Global Policies for Managing the Future Risks of Poliovirus Outbreaks: Insights and Lessons Learned Through Modeling

The success of the Global Polio Eradication Initiative promises to bring large benefits, including sustained improvements in quality of life (i.e., cases of paralytic disease and deaths avoided) and costs saved from cessation of vaccination. Obtaining and maintaining these benefits requires that policymakers manage the transition from the current massive use of oral poliovirus vaccine (OPV) to a world without OPV and free of the risks of potential future reintroductions of live polioviruses. This article describes the analytical journey that began in 2001 with a retrospective case study on polio risk management and led to development of dynamic integrated risk, economic, and decision analysis tools to inform global policies for managing the risks of polio. This analytical journey has provided several key insights and lessons learned that will be useful to future analysts involved in similar complex decision-making processes.     

The allocation of time to social and leisure activities as social indicators for the integration of aged ethnic minorities

One way in which a better understanding of social indicators to be employed in assessing the degree of social integration of aged ethnic minorities is to determine their time-use patterns for various daily activities. This paper reports on a research project undertaken in a planned community of La Villeneuve, France, which examines (a) the social context in which various activities took place, and (b) the duration and frequency of the activities. This was achieved through the combined techniques of time-budget analysis, social network mapping, and participant observations. Our data provides another dimension appropriate for social indicators research.     

The conical structure of adjustive behavior

Wellbeing and coping have usually been treated as separate topics in previous research. The present study proposes a general framework for adjustive behavior which incorporates both previous topics as special cases. This framework shows definitional similarities and differences among wellbeing, coping and further special cases. Empirical data are presented which show a correspondence between the facets of the definitional system and the matrix of intercorrelations of the variables defined thereby. The correspondence is that of a conex, that is, the facets correspond to a conical coordinate system for the SSA space that reproduces the correlation matrix.The data were gathered as part of the Continuing Survey conducted jointly by the Israel Institute of Applied Social Research and the Hebrew University's Communications Institute. The population sampled is the adult urban and rural Jewish population of Israel, over 20 years of age in mid-December 1977. Interviews were conducted in the home through closed questionnaires, 27 of the items being of adjustive behavior.     

Ask Prices, Offers, and Time to Sale in an Online Exchange

By examining an online computer exchange, we find that sellers who place higher nonbinding ask prices have higher outstanding offers and remain on the exchange longer, suggesting a willingness to hold out for higher offers. Additionally, higher ask prices deter buyers from making offers. The results are stronger in thinner market segments, suggesting that gains from waiting for a high price are greater when buyers' tastes are idiosyncratic. These relationships are consistent with models in which buyers engage in costly search and suggest that online exchanges may not eliminate the frictions related to bilateral transactions.     

Nonverbal behavior in families with adolescents

In fifty-three families, mothers, fathers and one adolescent were videotaped discussing two issues relevant to the adolescent's behavior: the aspects of their behavior they could change, and rules appropriate to life in the family. Family members later watched these videotapes and rated themselves and each other every 15 seconds on levels of perceived anxiety, involvement, strength and friend-liness. From these videotapes, each family member's behavior was also coded for the use of smiles, various face and head movements and gestures. Results revealed that adolescents looked frequently at both parents, but parents looked even more at each other and the adolescent. Adolescents smiled more than their parents, while mothers smiled and nodded their heads more than fathers. More nonverbal expresivity occurred in conversations between parents and daughters than between parents and sons, although these results were mainly due to the behavior of fathers with daughters. Ratings of involvement by parents were related to the adolescent's nonverbal behaviors, but other ratings were not. Mothers rated adolescents as more involved when they used more head up movements and nods. Fathers rated adolescents as more involved when they gazed and smiled more.