Small Group Predictions on an Uncertain Outcome: The Effect of Nondiagnostic Information

Research has established that exposure to a combination of diagnostic (i.e., relevant) and nondiagnostic (i.e., irrelevant) information results in predictions that are more regressive than predictions based on diagnostic information (Hackenbrack, 1992; Hoffman and Patton, 1997). This phenomenon has been labeled the dilution effect (e.g., Tetlock and Boettger, 1989) and has been documented when individuals make predictions. This study tests for the dilution effect when small groups make predictions, and examines the effect of using a procedure designed to reduce the dilution effect. Results indicate that group predictions are influenced by nondiagnostic information in the same manner as are individual predictions, and allowing participants to rate the diagnosticity of information prior to making predictions does not reduce the dilution effect.     

Information theory and risk in capital markets

The present empirical study applies the methodology of information theory to the problem of assessing and separating capital market risk, which is separated into its systematic and unsystematic components. Monthly return relatives for all securities traded on the New York Stock Exchange are examined for the period 1926 to 1971, which is segmented into six 7-year subperiods. The securities are combined into portfolios of various sizes and ranked. It is concluded that although both systematic and unsystematic risks have increased over the 45-year interval—particularly between the pre-1940 and post-1940 periods—they have maintained their relative share of the total risk over the same period.     

The Assessment of Probability Distributions from Expert Opinions with an Application to Seismic Fragility Curves

A method is developed for estimating a probability distribution using estimates of its percentiles provided by experts. The analyst's judgment concerning the credibility of these expert opinions is quantified in the likelihood function of Bayes'Theorem. The model considers explicitly the random variability of each expert estimate, the dependencies among the estimates of each expert, the dependencies among experts, and potential systematic biases. The relation between the results of the formal methods of this paper and methods used in practice is explored. A series of sensitivity studies provides insights into the significance of the parameters of the model. The methodology is applied to the problem of estimation of seismic fragility curves (i.e., the conditional probability of equipment failure given a seismically induced stress).     

METHODS FOR QUANTIFYING SUBJECTIVE PROBABILITIES AND MULTI-ATTRIBUTE UTILITIES*†

In many situations where normative decision-aiding techniques could be usefully applied, historical data are inadequate for estimating the required outcome probabilities, and economic methodologies are inadequate for estimating the aggregate utility derived from the several outcome attributes. In such cases it is often useful to obtain the required estimates in the form of expert judgments, i.e. to obtain subjective probabilities and multi-attribute utilities. Similarly, in many situations where behavioral decision processes are to be studied, it is necessary to scale the expectations and perceived values of the decision makers. This article describes the methods for eliciting subjective probabilities and multi-attribute utilities whose usefulness has been empirically studied and reported in the research literature. It also contains summary guidelines concerning the elicitation and use of such judgments.     

Proximity (Mis)perception: Public Awareness of Nuclear,Refinery, and Fracking Sites

Whether on grounds of perceived safety, aesthetics, or overall quality of life, residents may wish to be aware of nearby energy sites such as nuclear reactors, refineries, and fracking wells. Yet people are not always accurate in their impressions of proximity. Indeed, our data show that only 54% of Americans living within 25 miles of a nuclear site say they do, and even fewer fracking-proximal (30%) and refinery-proximal (24%) residents respond accurately. In this article, we analyze factors that could either help people form more accurate perceptions or distort their impressions of proximity. We evaluate these hypotheses using a large national survey sample and corresponding geographic information system (GIS) data. Results show that among those living in close proximity to energy sites, those who perceive greater risk are less likely to report living nearby. Conversely, social contact with employees of these industries increases perceived proximity regardless of actual distance. These relationships are consistent across each site type we examine. Other potential factors—such as local news use—may play a role in proximity perception on a case-by-case basis. Our findings are an important step toward a more generalizable understanding of how the public forms perceptions of proximity to risk sites, showing multiple potential mechanisms of bias.     

Longitudinal transactional relations among young children’s defiance and committed compliance and maternal assertive control

The main goal of this study was to more closely understand the direction of relations between maternal behavior and young children's defiance and committed compliance. We examined 256 mother–child dyads to explore developmental transactional relations between maternal assertive control, children's committed compliance, and children's defiance at 18 (T1), 30 (T2), and 42 (T3) months of age. After controlling for maternal gentle control, SES, and child sex, results showed parent effects for children's committed compliance, such that T1 maternal assertive control negatively predicted T3 committed compliance. Furthermore, toddlers’ behavior predicted T3 parenting; that is, toddlers’ T1 defiance positively predicted T3 maternal assertive control. Results of the present study indicate relatively long-term prediction (to 42 months) from both parent and child behaviors at 18 months of age, and the findings have implications for understanding the bidirectional and complex processes that account for young children's adaptive and maladaptive behaviors.     

Recommended Distributions for Exposure Factors Frequently Used in Health Risk Assessment

Although there has been nearly complete agreement in the scientific community that Monte Carlo techniques represent a significant improvement in the exposure assessment process, virtually all state and federal risk assessments still rely on the traditional point estimate approach. One of the rate-determining steps to a timely implementation of Monte Carlo techniques to regulatory decision making is the development of "standard" data distributions that are considered applicable to any setting. For many exposure variables, there is no need to wait any longer to adopt Monte Carlo techniques into regulatory policy since there is a wealth of data from which a robust distribution can be developed and ample evidence to indicate that the variable is not significantly influenced by site-specific conditions. In this paper, we propose several distributions that can be considered standard and customary for most settings. Age-specific distributions for soil ingestion rates, inhalation rates, body weights, skin surface area, tapwater and fish consumption, residential occupancy and occupational tenure, and soil-on-skin adherence were developed. For each distribution offered in this paper, we discuss the adequacy of the database, derivation of the distribution, and applicability of the distribution to various settings and conditions.     

An investigation of youths' attributions for unemployment and their political attitudes

This study investigated some hypotheses concerning the determinants of attributions for unemployment and the psychological consequences of unemployment in a randomly selected sample of 204 male school leavers. There was weak evidence for the hypothesis that the unemployed make more external attributions for unemployment, but none showing them to make less internal attributions. There was weak evidence that political party preference was related to internal and external attributions, and stronger evidence that a general tendency to see life as determined by chance was linked to external attributions. The unemployed were found to be more likely to support violent political action, to support the Labour Party, and to believe chance controlled their lives. Finally, external attributions were seen as more important than internal ones by all respondents. The results suggest that other factors, e.g. the mass media, may be influential in determining the nature of attributions and this is interpreted in the context of Moscovici's social representation theory.     

Analytic approaches to problems of a middle-sized defence department

The application of operational research to the problems of Canadian defence was very similar to that in Great Britain and the United States during World War II and through the 1950s. But because of the rapidly increasing costs of major weapon systems, since the 1960s systems analysis has been very thoroughly applied to the study of the large procurement programs, including far-reaching examination of their economic impact on the nation. Other problems of special interest to Canada which received analytical attention included peacekeeping and military involvement in activities such as maritime surveillance and search and rescue. Analytical studies have been extended into examination of logistics and manpower, and into economic, sociological, and strategic problems of concern to the Canadian defence department, including arms control. This type of research represents a considerable excursion from the original operational research, but is needed in the Canadian Department of National Defence.