Modeling without representation

How can mathematical models which represent the causal structure of the world incompletely or incorrectly have any scientific value? I argue that this apparent puzzle is an artifact of a realist emphasis on representation in the philosophy of modeling. I offer an alternative, pragmatic methodology of modeling, inspired by classic papers by modelers themselves. The crux of the view is that models developed for purposes other than explanation may be justified without reference to their representational properties.     

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.     

Linking the demands–control–support model to innovation: The moderating role of personal initiative on the generation and implementation of ideas

The demands–control–support model indicates that workers can use job control and social support for problem solving. We examined whether personal initiative moderated relationships between, on the one hand, job control used for problem solving and social support used for problem solving and, on the other hand, ideas generation and implementation. We operationalized job control used for problem solving as ‘changing aspects of work activities to solve problems’. We operationalized social support used for problem solving as ‘discussing problems to solve problems’. Using an experience sampling methodology, participants provided data for up to four times a day for up to five working days (N= 89). The extent to which people ‘changed aspects of their work activities to solve problems’ was associated with higher levels of ideas generation for people with high personal initiative. The extent to which people ‘discussed problems to solve problems’ was associated with higher levels of ideas implementation for people with high personal initiative.     

A correction for recruitment bias in norms derived from meta-analysis

Normative comparisons are an integral component of neuropsychological test interpretation and provide the basis for an inference of abnormal function and impairment. In order to remedy a deficit of normative standards for a large number of neuropsychology tests, Mitrushina, Boone, Razani, and D'Elia (2005) used the meta-analysis of studies that incorporated normal volunteers to create a type of normative standard for many tests in neuropsychology that were not adequately normed in the past. The present study examined this method by contrasting meta-analysis norms of the Wechsler Adult Intelligence Scale-Revised (WAIS-R; Wechsler, 1981) with its published quota norms. The study examined 12 experimental studies of the WAIS-R that included normal, control volunteers (N = 2,147). These were combined by meta-analysis, and the summary scores were compared. The meta-analysis revealed a significant sampling bias with studies recruiting more White and higher educated respondents than indicated by the U.S. Census. This bias was successfully corrected using Monte Carlo simulation and adjustments for quota sampling. The corrections could be applied to all meta-analysis norms currently in use and bring them in line with the U.S. Census demographics.     

Mindfulness-Based Stress Reduction (MBSR) for Primary School Teachers

Stress within the teaching profession has a negative impact on the health and well-being of individual teachers and on retention and recruitment for the profession as a whole. There is increasing literature to suggest that Mindfulness is a useful intervention to address a variety of psychological problems, and that Mindfulness-Based Stress Reduction (MBSR) is a particularly helpful intervention for stress. We investigated the effects of teaching a MBSR course to primary school teachers to reduce stress. The MBSR course was taught to a group of primary school teachers and evaluated to establish its effects on levels of anxiety, depression, and stress, as well as movement towards a stated goal and changes in awareness. The results showed improvement for most participants for anxiety, depression, and stress, some of which were statistically significant. There were also significant improvements on two of the four dimensions of a mindfulness skills inventory. These results suggest that this approach could be a potentially cost-effective method to combat teacher stress and burnout.