(M,S)-optimal row-column designs

Row-column designs may be considered to have two blocking schemes, namely the treatments by rows and treatments by columns component block designs. The (M,S)-optimality criterion is applied to row-column designs, and che connection between the (M,S)-optimal design and its component block designs is demonstrated.     

Career Techniques and Interventions: Themes From an International Conversation

The need for appropriate, timely, and increasingly comprehensive career development and education programs continues to escalate. It is interesting that despite the differences in cultures, religions, economies, political systems, and education structures, many countries face similar challenges when designing and implementing career development programs. Sharing and adapting career development interventions and techniques cross‐culturally appear to be viable strategies for implementing or enhancing programs, provided the concepts and materials are tailored to the countries' unique requirements.     

A GUIDE TO THE PITFALLS OF IDENTIFYING PRICE DISCRIMINATION

This paper demonstrates that plausible cost-based explanations exist for what are commonly perceived to be cases of price discrimination. We explain such commonly discussed problems as the price spreads of retail gasoline products, the "high" price of dinners at restaurants, the "high" price of popcorn at movie theaters, and the fact that airline ticket prices vary with how long the ticket is purchased before the flight's departure. Our explanations benefit from not relying on consumer ignorance or implicit collusion among numerous sellers.     

Exposure Assessment: Then, Now, and Quantum Leaps in the Future

Health risk assessments have become so widely accepted in the United States that their conclusions are a major factor in many environmental decisions. Although the risk assessment paradigm is 10 years old, the basic risk assessment process has been used by certain regulatory agencies for nearly 40 years. Each of the four components of the paradigm has undergone significant refinements, particularly during the last 5 years. A recent step in the development of the exposure assessment component can be found in the 1992 EPA Guidelines for Exposure Assessment. Rather than assuming worst-case or hypothetical maximum exposures, these guidelines are designed to lead to an accurate characterization, making use of a number of scientific advances. Many exposure parameters have become better defined, and more sensitive techniques now exist for measuring concentrations of contaminants in the environnment. Statistical procedures for characterizing variability, using Monte Carlo or similar approaches, eliminate the need to select point estimates for all individual exposure parameters. These probabilistic models can more accurately characterize the full range of exposures that may potentially be encountered by a given population at a particular site, reducing the need to select highly conservative values to account for this form of uncertainty in the exposure estimate. Lastly, our awareness of the uncertainties in the exposure assessment as well as our knowledge as to how best to characterize them will almost certainly provide evaluations that will be more credible and, therein, more useful to risk managers. If these refinements are incorporated into future exposure assessments, it is likely that our resources will be devoted to problems that, when resolved, will yield the largest improvement in public health.     

EXAMINING THE MULTIFACETED NOTION OF ISOMORPHISM IN MARRIAGE AND FAMILY THERAPY SUPERVISION: A QUEST FOR CONCEPTUAL CLARITY

The notion of isomorphism has been recommended as a comceptual framework to guide the practice of marrige and family therapy (MFT) supervision. The term is frequently cited in the MFT training literature but is often used in different ways. A panel of MFT supervirors rated the impotance and relevance to both therapy and supervision of a large pool of variables. The majority of variables were found to be a equally relevant or isomorphic to the domains of MFT and MFT supervisoin. A qualitative interview with a small subset of the panelists suggested that the concept, to varying degrees, has influenced their work as supervisors. The implications of the results for theory development, research, and supervisory practices are discussed.     

The Social Transformation of Trust in Government

The phenomenon of declining political trust among the American public has been widely discussed, with the explanations often focusing on specific historical events or the unique problems of American political institutions. We first demonstrate that public doubts about politicians and government are spreading across almost all advanced industrial democracies. The pervasiveness of this trend suggests that common social forces are affecting these nations, and we examine the social correlates of the decrease in trust. We find the greatest declines are among the better-educated and upper social status. These results suggest that changing citizen expectations, rather than the failure of governments, are prompting the erosion of political support in advanced industrial democracies.     

Building blocks for graphical belief models

The graphical belief model is a versatile tool for modeling complex systems. The graphical structure and its implicit probabilistic and logical independence conditions define the relationships between many of the variables of the problem. The graphical model is composed of a collection of local models:models of both interactions between the variables sharing a common hyperedge and information about single variables. These local models can be constructed with either probability distributions or belief functions. This paper takes the latter approach and describes simple models for univariate and multivariate belief functions. The examples are taken from both reliability and knowledge representation problems.     

Obstacles to research analysis

1. The homeless population is composed of subgroups with varying mental health status and needs. 2. Different research designs and data collection methods require differing psychosocial abilities and skills on the part of the respondent. 3. As a result of the psychosocial abilities required and method of sampling, studies are likely to either underrepresent or overrepresent the severely mentally ill homeless. 4. Caution must be exercised in drawing conclusions from any one study.