Combining Opinions for Use in Bayesian Networks: A Measurement Error Approach

Bayesian networks (BNs) are graphical probabilistic models used for reasoning under uncertainty. These models are becoming increasingly popular in a range of fields including engineering, ecology, computational biology, medical diagnosis and forensics. In most of these cases, the BNs are quantified using information from experts or from users' opinions. While this quantification is straightforward for one expert, there is still debate about how to represent opinions from multiple experts in a BN. This paper proposes the use of a measurement error model to achieve this. The proposed model addresses the issues associated with current methods of combining opinions such as the absence of a coherent probability model, the loss of the conditional independence structure of the BN and the provision of only a point estimate for the consensus. The proposed model is applied to a subnetwork (the three final nodes) of a larger BN about wayfinding in airports. It is shown that the approach performs well than do existing methods of combining opinions.     

Affect versus cognition: Wishful thinking on election day: An analysis using exit poll data from Belgium

Citizens tend to overestimate the electoral success of their preferred party. We investigate the extent to which Belgian voters overestimate the result of the party that they vote for and the factors that explain which voters do so more than others. Our focus is on the impact of educational attainment and partisan attachment on the overestimation of one’s party’s result. Previous research in this field has relied on data gathered in the months before the elections, which introduces a substantial amount of uncertainty and variation over time into the measurements of citizens’ vote share estimations. As an alternative, we investigate voters’ estimations of their party’s electoral success by means of data gathered in an exit poll survey. Our results show partisan attachments to have a strong impact on overestimations, which suggests that a wishful thinking mechanism is in play. Furthermore, we find that the extent to which partisan attachments increase citizens’ overestimations depends on a voter’s level of education.     

Reflections on per diems in international development projects: Barriers to and enablers of the project cycle

The concept of what a per diem is and who should receive one is a complex idea that, within the development context, can either support or hinder the achievement of development projects’ goals. This paper seeks to explain the evolving nature of per diems and their use within the development context; explore how they serve as barriers or enablers in achieving project goals; and touch on their impact on the development project cycle. Through a 3-year-long internationally funded development programme in Malawi and South Africa, the authors compare lessons drawn from their experience with existing literature to determine the practicalities of paying per diems and address the question: To what extent do per diems support or hinder international development projects?     

FARM TENURE AND FARMING PRACTICE

The performance of wholly owned, wholly rented and mixed tenure farms in the Farm Management Survey sample for England and Wales is compared on a range of criteria, controlling farm size and type. Mixed tenure farms are found to perform noticeably better than ‘pure’ tenure types. Possible explanations for inter-tenure differences in performance are reviewed under the headings of capital provision, farmer motivation and resource mobility. Evidence from the FMS and from interviews with 48 farmers provide only weak support for hypotheses relating performance to capital endowments, the ‘spur’ of market rents or asset appreciation. Findings on changes in farm size and tenure, however, suggest that tenure could be determined by, rather than being a determinant of, farm performance.     

THE ECONOMICS OF COMMUTING AND THE URBAN LABOUR MARKET

ABSTRACT. The spatial distribution of households and firms, or urban spatial structure, is a core element of the study of urban economics and the crucial determinant of commuting patterns. This paper examines developments in the analysis of urban spatial structure and commuting are related to the urban labour market—that is the analysis of labour supply and labour demand in a spatial context. These developments have been overlooked in the traditional approach to urban structure and commuting where most attention has been devoted to the markets for land and housing rather than the market for labour. Yet a little reflection suggests that the labour market might have a great deal to do with the location decisions of households and firms, and hence with commuting patterns. We argue that much criticism of the economic analysis of urban structure and commuting can be addressed by explicit incorporation of the labour market into the conventional model of urban location. This criticism includes findings that the theory cannot explain the tendency for richer households to live farther from the central business district and commute farther to work (Wheaton, 1977) and findings of substantial unexplained or 'wasteful' commuting according to conventional theory (Hamilton, 1982). The paper begins by outlining the basic model of residential location and commuting (Section 2). We then consider extensions that involve the introduction of labour supply decisions and which determine the value of commuting time (Section 3). More recent extensions involve the introduction of decentralized workplaces (Section 4) and, logically, the issues of job search and migration (Section 5). We conclude with a summary of the progress in incorporating labour market behaviour into the analysis of urban structure and commuting and our suggestions for further research in this area.     

The effects of schematic memory on imaginal information processing: An empirical assessment

The relationship between verbal and nonverbal modes of processing consumer information was examined in an investigation of schematic processing, a predominantly verbal mode, and visual imagery, a nonverbal method of information processing. It was found that individuals with a schema for a marketing event exhibited both a higher incidence and greater vividness of imagery during retrieval than did subjects without a schema. No differences were observed in either the frequency or clarity of images related to actions of varying degrees of abstraction in the event schema. These results indicate interdependence between schematic and imaginal processing consistent with the Cyclical Processing Model (Hampson and Morris 1979). A number of implications, both methodological and strategic, are developed from the observed relationship between imaginal and schematic information processing.