Coefficient alpha is the most popular measure of reliability (and certainly of internal consistency reliability) reported in psychological research. This is noteworthy given the numerous deficiencies of coefficient alpha documented in the psychometric literature. This mismatch between theory and practice appears to arise partly because users of psychological scales are unfamiliar with the psychometric literature on coefficient alpha and partly because alternatives to alpha are not widely known. We present a brief review of the psychometric literature on coefficient alpha, followed by a practical alternative in the form of coefficient omega. To facilitate the shift from alpha to omega we also present a brief guide to the calculation of point and interval estimates of omega using a free, open source software environment. | P a g eThe construction and application of psychometric scales has become accepted best practice when attempting to measure human performance and behaviour. The implications of test "quality" for the individual and society are unquestioned. Statistical procedures that attempt to assess reliability have acquired the status of ingrained conventions, with certain types of analyses being routinely adopted. The predominant framework under which most such procedures fall is Classical Test Theory (CTT) (e.g., see Lord & Novick, 1968). This is the most popular way of conceptualising how a scale should perform and function. In recent years improved approaches to reliability estimation have been advocated by psychometricians. Yet, despite a widespread dissemination and publication of alternatives, there remains a staunch resistance to advancements in the interpretation, application, and reporting of a scale"s reliability, particularly when it comes to internal consistency.The APA Task Force on Statistical Inference (Wilkinson and APA Task Force on Statistical Inference, 1999), placed emphasis on the correct use and treatment of reliability estimates.The most common type of reliability estimate reported in articles published by the American Psychological Association were internal consistency estimates (as opposed to test-retest or parallel forms). These accounted for 75% of all reported reliabilities (Hogan et al., 2000). The most common means of assessing internal consistency in the social sciences is that of coefficient alpha -also termed Cronbach"s alpha (alpha) (following Cronbach"s influential 1951 paper). This has become a routinely relied upon statistic for estimating a scale"s internal consistency. A recent search by the current authors (via Google Scholar®, 2012) confirms its prevalence -showing it to have been cited some 17,608 times since its original publication.However, as Cronbach himself stated, "The numerous citations to my paper by no means 3 | P a g e indicate that the person who cited it had read it, and does not even demonstrate that he had looked at it." (Cronbach & Shavelson, 2004, p.392).Reflective of Cronbach"s comment, researchers" understanding of reliability analysis is g...

No abstract

The Operational Multiscale Environment Model with Grid Adaptivity (OMEGA) and its embedded Atmospheric Dispersion Model is a new atmospheric simulation system for real-time hazard prediction, conceived out of a need to advance the state of the art in numerical weather prediction in order to improve the capability to predict the transport and diffusion of hazardous releases. OMEGA is based upon an unstructured grid that makes possible a continuously varying horizontal grid resolution ranging from 100 km down to 1 km and a vertical resolution from a few tens of meters in the boundary layer to 1 km in the free atmosphere. OMEGA is also naturally scale spanning because its unstructured grid permits the addition of grid elements at any point in space and time. In particular, unstructured grid cells in the horizontal dimension can increase local resolution to better capture topography or the important physical features of the atmospheric circulation and cloud dynamics. This means that OMEGA can readily adapt its grid to stationary surface or terrain features, or to dynamic features in the evolving weather pattern. While adaptive numerical techniques have yet to be extensively applied in atmospheric models, the OMEGA model is the first model to exploit the adaptive nature of an unstructured gridding technique for atmospheric simulation and hence real-time hazard prediction. The purpose of this paper is to provide a detailed description of the OMEGA model, the OMEGA system, and a detailed comparison of OMEGA forecast results with data.

No abstract

Due to its potential to concurrently improve work-related wellbeing (WRW) and job performance, occupational stakeholders are becoming increasingly interested in the applications of meditation. The present study conducted the first randomized controlled trial to assess the effects of meditation on outcomes relating to both WRW and job performance.Office-based middle-hierarchy managers (n = 152) received an eight-week meditation intervention (Meditation Awareness Training; MAT) or an active control intervention. MAT participants demonstrated significant and sustainable improvements (with strong effect sizes) over control-group participants in levels of work-related stress, job satisfaction, psychological distress, and employer-rated job performance. There are a number of novel implications: (i) meditation can effectuate a perceptual shift in how employees experience their work and psychological environment and may thus constitute a cost-effective WRW intervention, (ii) meditation-based (i.e., present-moment-focussed) working styles may be more effective than goal-based (i.e., future-orientated) working styles, and (iii) meditation may reduce the separation made by employees between their own interests and those of the organizations they work for.