A Geometrical Interpretation of Collinearity: A Natural Way to Justify Ridge Regression and Its Anomalies

Justifying ridge regression from a geometrical perspective is one of the main contributions of this paper. To the best of our knowledge, this question has not been treated previously. This paper shows that ridge regression is a particular case of raising procedures that provide greater flexibility by transforming the matrix X associated with the model. Thus, raising procedures, based on a geometrical idea of the vectorial space associated with the columns of matrix X , lead naturally to ridge regression and justify the presence of the well-known constant k on the main diagonal of matrix X ^′ X . This paper also analyses and compares different alternatives to raising with respect to collinearity mitigation. The results are illustrated with an empirical application.     

Union games: technological unemployment

Summary. Given a production economy, we define union games by considering strategic behavior of the suppliers of factors. We refer to the Nash equilibria of this game as union equilibria. We analyze situations where the unemployment of factors is supported as a union equilibrium. The degree of unemployment depends on technological conditions. This allows us to model a source of unemployment which differs from the usual sources provided in the literature. We state a limit result that demonstrates that, as the market power of unions decreases, the corresponding sequence of union equilibria converges to the Walrasian equilibrium, that is, to full employment of factors. We also provide some examples that illustrate the main results.Received: 21 October 2004, Revised: 14 December 2004, JEL Classification Numbers: D51, C72. Correspondence to: Emma Moreno-GarcíaE. Moreno acknowledges financial support from the Research Grant BEC2000-1388-C04-01 (Ministerio de Ciencia y Tecnología and FEDER). G. Fernández de Córdoba and E. Moreno acknowledge financial support from the Research Grant SA091/02 from Junta de Castilla y León. We are indebted to C. Alós-Ferrer, C. Pita, D. Anisi, J. A. Ortega, F. Jimeno, J. P. Torres-Martínez, M. Steinert and C. Hervés for helpful comments and insights. We are particularly grateful to T. Kehoe and an anonymous referee for suggestions that improved this paper.     

Media visibility and corporate social responsibility investment evidence in Spain

Despite the extensive research in both the determinants and the results of corporate social responsibility (CSR), relatively few studies have considered extra-legal institutions as potential determinants of CSR. Our work fills this gap by looking at how media attention affects CSR over a long-term period in a continental European setting. Our results show that media coverage positively affects CSR. Additional scrutiny triggered by media coverage encourages dominant owners to signal their commitment to limiting self-dealing transactions and their orientation toward stakeholders' needs through CSR investments. Additionally, our results reveal that this signaling device offers greater benefits and lower costs in firms where controlling owners show a voting-cash flow wedge. Our results are relevant to different actors such as investors, auditors, and policy makers as they provide solid evidence that media coverage is an important driver of CSR orientation in a continental European setting.     

Using templates and linguistic patterns to define process performance indicators

Process performance management (PPM) aims at measuring, monitoring and analysing the performance of business processes (BPs), in order to check the achievement of strategic and operational goals and to support decision-making for their optimisation. PPM is based on process performance indicators (PPIs), so having an appropriate definition of them is crucial. One of the main problems of PPIs definition is to express them in an unambiguous, complete, understandable, traceable and verifiable manner. In practice, PPIs are defined informally – usually in ad hoc, natural language, with its well-known problems – or they are defined from an implementation perspective, hardly understandable to non-technical people. In order to solve this problem, in this article we propose a novel approach to improve the definition of PPIs using templates and linguistic patterns. This approach promotes reuse, reduces both ambiguities and missing information, is understandable to all stakeholders and maintains traceability with the process model. Furthermore, it enables the automated processing of PPI definitions by its straightforward translation into the PPINOT metamodel, allowing the gathering of the required information for their computation as well as the analysis of the relationships between them and with BP elements.     

Disaggregating and reaggregating work: Workers,management and the struggle over creating coherency and purpose in a context of work degradation

The article argues that whilst there is a growing sense of degradation and worsening conditions (disaggregation) of work in the cleaning sector in general, there are some important contradictions which require complex organisational responses. In the main, there is a growing sense of isolation in this work, yet also a growing perception of autonomy and workers having to use discretion in new and challenging ways. This article focuses on these issues and management responses to reaggregate the nature of such work, creating new forms of identity and activities intended to enhance (or address) the levels of stability and sustainability at work as well as in operational processes. This management conundrum means that they need to deal with a range of job‐related, skill‐oriented worker learning and also representation issues. These responses bring to the fore the contested nature of such forms of work and how they are changing.     

Estimation of Asymmetric Stochastic Volatility Models: Application to Daily Average Prices of Energy Products

Energy supply and demand, and as a consequence energy prices, are likely to represent one of the biggest challenges of the 21st century. Commodity markets exhibit increased volatility when there is little or no underutilized supply capability to meet natural fluctuations in demand. In the case of energy markets, the large capital requirements and significant lead times associated with energy production and delivery make them more susceptible to the imbalances in supply capability and demand. Energy price volatility has destructive impact on market agents, and this impact is intensified when the prices exhibit asymmetric volatility. This article pursues two aspects of the issue. First we consider general aspects, especially the asymmetric pattern of volatility of daily returns of different types of energy products. Then, we analyze the behaviour of daily returns by using traditional models of volatility that include AGARCH, TGARCH, EGARCH, and ARSV strategies, as well as a threshold asymmetric autoregressive stochastic volatility (TA-ARSV) model that we propose. The energy products considered in this analysis are probably the most relevant energy products for the economic activity of the nations and the economic relations between countries: Crude Oil (OPEC reference basket and London Brent index), Gasoline, Natural Gas, Butane, and Propane. We use spot prices and the time reference ranges from 1986–1993 to 2009 depending on the product.     

Content analysis research method with Nvivo-6 software in a PhD thesis: an approach to the long-term psychological effects on Chilean ex-prisoners survivors of experiences of torture and imprisonment

The aim of this paper is to review the usefulness of the software CAQDAS QSR—Nvivo-6 in a PhD. Thesis, which consisted of finding the long-term psychological effects of experiences of imprisonment and torture for political reasons in their Chilean survivors. For this research, it was created and administered an in-depth interview to 60 survivors, from which outcome was 9900 paragraphs, coded into 784 categories. The software QSR Nvivo-6 threw a report of frequencies, which were compared quantitatively using Pearson’s χ ² square test and cluster analysis. We conclude that the software facilitates the development of qualitative thematic content analysis, simplifying the coding, analysis and display of data. In Addition, it is very useful when working with large quantities of information, promoting the reliability and validity of studies. However, other aspects are also required to ensure the rigor of a qualitative study.