Estimation of the Coefficient of Variation with Minimum Risk: A Sequential Method for Minimizing Sampling Error and Study Cost

The coefficient of variation is an effect size measure with many potential uses in psychology and related disciplines. We propose a general theory for a sequential estimation of the population coefficient of variation that considers both the sampling error and the study cost, importantly without specific distributional assumptions. Fixed sample size planning methods, commonly used in psychology and related fields, cannot simultaneously minimize both the sampling error and the study cost. The sequential procedure we develop is the first sequential sampling procedure developed for estimating the coefficient of variation. We first present a method of planning a pilot sample size after the research goals are specified by the researcher. Then, after collecting a sample size as large as the estimated pilot sample size, a check is performed to assess whether the conditions necessary to stop the data collection have been satisfied. If not an additional observation is collected and the check is performed again. This process continues, sequentially, until a stopping rule involving a risk function is satisfied. Our method ensures that the sampling error and the study costs are considered simultaneously so that the cost is not higher than necessary for the tolerable sampling error. We also demonstrate a variety of properties of the distribution of the final sample size for five different distributions under a variety of conditions with a Monte Carlo simulation study. In addition, we provide freely available functions via the MBESS package in R to implement the methods discussed.     

Drugs,Sex, and Condoms: Identification and Interpretation of Race‐Specific Cultural Messages Influencing Black Gay and Bisexual Young Men Living with HIV

Black gay and bisexual young men carry a disproportionate burden of HIV in the United States. This study explored Black gay and bisexual young men living with HIV's identification and interpretation of race‐specific cultural messages regarding substance use, sexual activity, and condom use. A total of 36 Black gay and bisexual young men living with HIV (ages 16–24, mean = 20.6 years) from four geographically diverse regions of the United States participated in qualitative in‐depth interviews. Results from this study elucidate the ways in which these young men interpret various forms of race‐specific cultural messages and experiences regarding substance use, sexual activity, and condom use. Participants discussed cultural messages and experiences promoting and discouraging condoms and substance use. Regarding sexual activity, only messages and experiences promoting sex were reported. Across all three categories, messages and experiences promoting risk were predominant. Data further revealed that socially transmitted cultural messages received by young men emanated from multiple sources, such as family, peers, sexual partners, community/neighborhood, and the broader society. Race‐specific cultural messages and experiences should be addressed in interventions for this population, and programs should assist young men in developing a critical consciousness regarding these messages and experiences in order to promote health and well‐being.     

Fetal Risks,Relative Risks,and Relatives' Risks

Several factors related to fetal risk render it more or less acceptable in justifying constraints on the behavior of pregnant women. Risk is an unavoidable part of pregnancy and childbirth, one that women must balance against other vital personal and family interests. Two particular issues relate to the fairness of claims that pregnant women are never entitled to put their fetuses at risk: relative risks and relatives' risks. The former have been used—often spuriously—to advance arguments against activities, such as home birth, that may incur risk; the latter implicate the nature of relationships in determining the acceptability of coercing or precluding activities. Motivated reasoning by clinicians and judges leads to inaccurate risk assessments, and judgments based on false claims to objectivity. Such judgments undermine the moral and legal standing of pregnant women and do not advance the interests of fetuses, pregnant women, families, or states.     

Who Is at Risk for Psychological Distress in Genetic Testing Programs for Hereditary Cancer Disorders?

Presymptomatic identification of disease gene carriers is becoming an increasingly common part of the clinical management of hereditary cancer disorders. With an expected increase in the number of requests for DNA testing and the limited resources for counseling, the amount of time genetic counselors are able to spend with test candidates will decrease. It is therefore important for counselors to identify persons at risk for psychological distress. Based on a review of experiences with Huntington disease and cancer patients, we describe factors likely to evoke distress in genetic cancer candidates. We also discuss the sometimes widely different ways that test candidates and their partners respond to genetic testing. By exploring risk factors for distress in relevant domains of the research, we can offer counselors guidelines for determining who may need extra counseling.     

Assessing risky public investments with MUSTARD

This paper presents a practical implementation of multicriteria methodologies based on the UTA model by Jacquet‐Lagrèze and Siskos and Quasi‐UTA model by Beuthe and Scannella, which are specified with a non‐linear, but piecewise linear, additive utility function. In contrast with the general UTA model, the Quasi‐UTA specification structures the partial utilities as recursive exponential functions of only one curvature parameter. This allows for a reduction of the quantity of information necessary to build the utility function. The software MUSTARD implements different variants of these models. Firstly, it offers the basic deterministic UTA model of disaggregation, but also its first programmed stochastic version. In both cases, the software proceeds stepwise and interactively helping the decision maker to formulate the problem and state preferences between projects; in the stochastic case, the decision maker is even helped to build the criteria distributions. The Quasi‐UTA specification can be introduced in this disaggregation model. Secondly, the software offers an aggregation model whereby the Quasi‐UTA partial utility functions are built separately through specific questioning processes. The questions relating to deterministic criteria are of the ‘direct rating type’, while those of the stochastic criteria are either of the ‘variable probability’ or the ‘variable outcome’ type. The criteria weights can be assessed by the ‘swing weight’ method or by a UTA‐II side‐program. As an example as well as a test of the Quasi‐UTA aggregation approach, the paper presents its application to a real problem of selecting road investment projects in Belgium. Several experts and civil servants were interviewed, and their individual utility functions derived. The projects are ranked according to their rate of return, which is computed on the basis of the projects certain equivalent money value. Copyright © 2002 John Wiley & Sons, Ltd.     

Investigating the roots of the favourite–longshot bias: an analysis of decision making by supply‐ and demand‐side agents in parallel betting markets

This paper offers new insights into the behavioural origins of the ‘favourite–longshot’ bias — an established feature of betting markets, whereby longshots win less often than the subjective probabilities imply and favourites more often. A number of alternative explanations has been offered for this phenomenon but the main debate focuses on whether it is caused by the behaviour of those supplying betting markets (bookmakers) or of the demand‐side agents in these markets (bettors) . This study analyses a new data source which offers detailed information for a large sample of recent UK horseraces on decision‐making behaviour within the parimutuel and the parallel bookmaker‐based betting markets. The results offer strong evidence for the existence of the ‘favourite–longshot’ bias in bookmaker‐based markets, with a corresponding absence of such an effect in the parimutuel case. These results offer support for the view that the origins of the ‘favourite–longshot’ bias lie principally in the decisions of bookmakers rather than in the decisions of bettors. Copyright © 2000 John Wiley & Sons, Ltd.     

Making sense of mentoring or mentoring making sense? Reflections on the mentoring process by adult mentors with young people†

This paper sets out to look at the processes of mentoring from the perspectives of adult mentors who were interviewed as part of a wider study of young people's perceptions and understandings of informal mentoring processes. It seeks to clarify the processes of mentoring within the context of the ‘risk society’ by posing the question, how do young people and mentors perceive these processes? What do mentors get out of the mentoring relationship? Findings from a qualitative study of informal mentoring relationships are drawn on to suggest that the mentors perceive the experience of being identified as a mentor and the processes of mentoring in highly positive terms. It is argued that this provides a form of ‘cultural capital for mentors’ in helping them to make sense of the challenges and dilemmas they face as adults. It is concluded that this finding has important implications for the design of mentoring interventions with young people. Copyright © 2000 John Wiley & Sons, Ltd.     

The affect heuristic in judgments of risks and benefits

This paper re‐examines the commonly observed inverse relationship between perceived risk and perceived benefit. We propose that this relationship occurs because people rely on affect when judging the risk and benefit of specific hazards. Evidence supporting this proposal is obtained in two experimental studies. Study 1 investigated the inverse relationship between risk and benefit judgments under a time‐pressure condition designed to limit the use of analytic thought and enhance the reliance on affect. As expected, the inverse relationship was strengthened when time pressure was introduced. Study 2 tested and confirmed the hypothesis that providing information designed to alter the favorability of one's overall affective evaluation of an item (say nuclear power) would systematically change the risk and benefit judgments for that item. Both studies suggest that people seem prone to using an ‘affect heuristic’ which improves judgmental efficiency by deriving both risk and benefit evaluations from a common source—affective reactions to the stimulus item. Copyright © 2000 John Wiley & Sons, Ltd.     

个体解决三项系列问题的心理模型

该研究设计了2种实验条件,对360名6-19岁个体解决三项系列问题的能力发展进行了研究,旨在讨论个体解决三项系列问题的心理模型的发展问题,结果表明：(1)6-19岁个体对三项系列问题中有必然逻辑答案的题目的判断能力的发展速度比较平稳;(2)个体对三项系列问题中有必然逻辑答案的题目的判断能力先于对没有逻辑答案的题目,6-9岁个体对三项系列问题中没有必然逻辑答案的题目的判断能力的发展速度低于10岁以后的个体;(3)空间模型、语义模型、语义一空间混合模型和枢纽项比较模型是相互补充的,是在不同认知发展阶段依一定次序,按一定的阶段逐渐形成的,经历了5个不同的发展阶段,最终形成以枢纽项比较模型为核心、四种心理模型并存于个体的心理结构之中的复合模型。