805 resultados para GRANGER CAUSALITY
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Fundamental principles of precaution are legal maxims that ask for preventive actions, perhaps as contingent interim measures while relevant information about causality and harm remains unavailable, to minimize the societal impact of potentially severe or irreversible outcomes. Such principles do not explain how to make choices or how to identify what is protective when incomplete and inconsistent scientific evidence of causation characterizes the potential hazards. Rather, they entrust lower jurisdictions, such as agencies or authorities, to make current decisions while recognizing that future information can contradict the scientific basis that supported the initial decision. After reviewing and synthesizing national and international legal aspects of precautionary principles, this paper addresses the key question: How can society manage potentially severe, irreversible or serious environmental outcomes when variability, uncertainty, and limited causal knowledge characterize their decision-making? A decision-analytic solution is outlined that focuses on risky decisions and accounts for prior states of information and scientific beliefs that can be updated as subsequent information becomes available. As a practical and established approach to causal reasoning and decision-making under risk, inherent to precautionary decision-making, these (Bayesian) methods help decision-makers and stakeholders because they formally account for probabilistic outcomes, new information, and are consistent and replicable. Rational choice of an action from among various alternatives-defined as a choice that makes preferred consequences more likely-requires accounting for costs, benefits and the change in risks associated with each candidate action. Decisions under any form of the precautionary principle reviewed must account for the contingent nature of scientific information, creating a link to the decision-analytic principle of expected value of information (VOI), to show the relevance of new information, relative to the initial ( and smaller) set of data on which the decision was based. We exemplify this seemingly simple situation using risk management of BSE. As an integral aspect of causal analysis under risk, the methods developed in this paper permit the addition of non-linear, hormetic dose-response models to the current set of regulatory defaults such as the linear, non-threshold models. This increase in the number of defaults is an important improvement because most of the variants of the precautionary principle require cost-benefit balancing. Specifically, increasing the set of causal defaults accounts for beneficial effects at very low doses. We also show and conclude that quantitative risk assessment dominates qualitative risk assessment, supporting the extension of the set of default causal models.
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Study Design. Retrospective Objective. To predict satisfaction with medical rehabilitation. Summary of Background Data. While spinal cord injury (SCI) patient satisfaction with life and community services has been investigated, satisfaction with medical rehabilitation has not. Methods. Information submitted to the Uniform Data System for Medical Rehabilitation ( 1998 - 2001) by 134 hospitals/rehabilitation facilities in the United States (n = 6,205 patients with SCI) was examined. Predictors were sociodemographic variables, Case Mix Groupings (CMG) ( 401 - 505, 5001), length of stay, rehospitalization, followup therapy, and health maintenance. Satisfaction was assessed at a mean of 92.2 days (SD 11.9 days) postdischarge. Data were analyzed according to who reported the outcome ( patient, n = 3,858 or family/other, n = 1,869). Statistical modeling was conducted using logistic regression. Results. High overall satisfaction was reported (94%). Significant predictors for the patient report data were CMG and rehospitalization. Compared with CMG 5001 ( short stay,
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Ischemia-reperfusion (I/R) injury is a common clinical event with the potential to seriously affect, and sometimes kill, the patient. Interruption of blood supply causes ischemia, which rapidly damages metabolically active tissues. Paradoxically, restoration of blood flow to the ischemic tissues initiates a cascade of pathology that leads to additional cell or tissue injury. I/R is a potent inducer of complement activation that results in the production of a number of inflammatory mediators. The use of specific inhibitors to block complement activation has been shown to prevent local tissue injury after I/R. Clinical and experimental studies in gut, kidney, limb, and liver have shown that I/R results in local activation of the complement system and leads to the production of the complement factors C3a, C5a, and the membrane attack complex. The novel inhibitors of complement products may find wide clinical application because there are no effective drug therapies currently available to treat I/R injuries.
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Objectives To identify and examine differences in pre-existing morbidity between injured and non-injured population-based cohorts. Methods Administrative health data from Manitoba, Canada, were used to select a population-based cohort of injured people and a sample of non-injured people matched on age, gender, aboriginal status and geographical location of residence at the date of injury. All individuals aged 18-64 years who had been hospitalized between 1988 and 1991 for injury (International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) code 800-995) (n = 21032), were identified from the Manitoba discharge database. The matched non-injured comparison group comprised individuals randomly selected 1: 1 from the Manitoba population registry. Morbidity data for the 12 months prior to the date of the injury were obtained by linking the two cohorts with all hospital discharge records and physician claims. Results Compared to the non-injured group, injured people had higher Charlson Comorbidity Index scores, 1.9 times higher rates of hospital admissions and 1.7 times higher rates of physician claims in the year prior to the injury. Injured people had a rate of admissions to hospital for a mental health disorder 9.3 times higher, and physician claims for a mental health disorder 3.5 times higher, than that of non-injured people. These differences were all statistically significant (P < 0.001). Conclusion Injured people were shown to differ from the general non-injured population in terms of pre-existing morbidity. Existing population estimates of the attributable burden of injury that are obtained by extrapolating from observed outcomes in samples of injured cases may overestimate the magnitude of the problem.
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The authors examine the evidence on the relationship between inflation and productivity growth for nine Asian economies using causality analysis in a multivariate model with money supply as a possible effective monetary policy tool. The inflation-productivity growth relationship is found to be non-uniform, as the evidence of uni-directional, bi-directional, and no causality between the two variables is varied and significant for some countries and insignificant for others. An attempt is made to explain the inflation-productivity nexus for these countries and to discuss implications for anti-inflationary policies such as inflation targeting.
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The interest in experiential and embodied aspects of brand and other product usage is under-represented in tourism orientated research, which generally falls to develop a contextualised understanding of the relationships between products and consumers, and within this in particular, considerations of individuality and self, embodiment, emotion and sensation. Aiming to `reverse the causality' (Lannon and Cooper 1983:201) of consumption focused tourism research, in this paper, I draw on the tourism experiences of Audrey, a participant in a larger study to reveal how, rather than just `consuming', tourism consumers interpret the meaning and values in a wide range of products and objects, weaving individual, rich, sensory, embodied experiences which are informed by the interactions and relationships with activities and products, and by their own personalities, past experiences and aspirations. Audrey is highly conscious of her self and of elsewhereness, hers are fragile, self-indulgent, tactile experiences which offer the freedom to step out of everyday life roles into other time and situational spheres where environment, objects and sensory stimulation are paramount. [ABSTRACT FROM AUTHOR]
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This paper reinvestigates the energy consumption-GDP growth nexus in a panel error correction model using data on 20 net energy importers and exporters from 1971 to 2002. Among the energy exporters, there was bidirectional causality between economic growth and energy consumption in the developed countries in both the short and long run, while in the developing countries energy consumption stimulates growth only in the short run. The former result is also found for energy importers and the latter result exists only for the developed countries within this category. In addition, compared to the developing countries, the developed countries' elasticity response in terms of economic growth from an increase in energy consumption is larger although its income elasticity is lower and less than unitary. Lastly. the implications for energy policy calling for a more holistic approach are discussed. (c) 2006 Elsevier Ltd. All rights reserved.
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O objetivo deste trabalho é testar a teoria da Paridade de Poder de Compra em sua versão absoluta e relativa para o Brasil no período de 1995 a 2010, utilizando procedimentos da econometria visando estabelecer através de testes de hipóteses a validação ou rejeição da teoria da Paridade do Poder de Compra. Para a verificação serão utilizados os testes de Dickey-Fuller (DF), Dickey-Fuller Ampliado (ADF) e testes de Cointegração de Engle e Granger e Joahansen. Adotamos para o estudo os países EUA e Brasil, tendo em vista o fluxo de comércio entre estes países e sua importância na economia mundial. Através dos índices de preço IPA e PPI analisarse- á a validação da teoria da Paridade de Poder de Compra em sua versão relativa e absoluta, chegando-se a conclusão de aceitação de sua versão relativa e rejeição de sua versão absoluta.
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Questo lavoro tratta dei tassi e della rischiosità delle imprese. In particolare, si esamina il collegamento esistente fra i tassi a medio-lungo termine europei e quelli americani e come ad esempio i tassi d’interesse forward dell’Eurirs derivino dall’euro e dalla struttura a termine dei tassi IRS sul dollaro. Le tecniche econometriche applicate sono la cointegrazione, la causalità di Granger, il GMM, il metodo di Rigobon e Sack (2004). Nella seconda parte si introduce una relazione per la stima dell’EONIA prima e durante la politica di full allottment della BCE. Nell’analisi empirica si usano tre differenti stimatori: OLS, Tobit e NLS e si considera il fatto che l’EONIA si muove all’interno del corridoio dei tassi, (formato dal tasso sui deposit facilities e sui marginal lending). L’ultima parte è dedicata allo studio della rischiosità delle imprese per mezzo dei principali indicatori di rischio (le tre formulazioni dello Z score di Altman e l’indice di Ohlson) a livello italiano ed europeo. I metodi d’analisi statistica utilizzati sono la regressione quantile, il Logit e il Probit.
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Electoral Rules and Leader Selection: Experimental Evidence from Ugandan Community Groups. Despite a large body of work documenting how electoral systems affect policy outcomes, less is known about their impact on leader selection. We study this by comparing two types of participatory decision making in Ugandan community groups: (i) vote by secret ballot and (ii) open discussion with consensus. Random assignment allows us to estimate the causal impact of the rules on leader types and social service delivery. Vote groups are found to elect leaders more similar to the average member while discussion group leaders are positively selected on socio-economic characteristics. Further, dropout rates are significantly higher in discussion groups, particularly for poorer members. After 3.5 years, vote groups are larger in size and their members save less and get smaller loans. We conclude that the secret ballot vote creates more inclusive groups while open discussion groups favor the already economically successful. Preparing for Genocide: Community Meetings in Rwanda. How do political elites prepare the civilian population for participation in violent conflict? We empirically investigate this question using data from the Rwandan Genocide in 1994. Every Saturday before 1994, Rwandan villagers had to meet to work on community infrastructure. The practice was highly politicized and, according to anecdotal evidence, regularly used by the political elites for spreading propaganda in the years before the genocide. This paper presents the first quantitative evidence of this abuse of the community meetings. To establish causality, we exploit cross-sectional variation in meeting intensity induced by exogenous weather fluctuations. We find that an additional rainy Saturday resulted in a five percent lower civilian participation rate in genocide violence. Selection into Borrowing: Survey Evidence from Uganda. In this paper, I study how changes to the standard credit contract affect loan demand and selection into borrowing, using a representative sample of urban micro enterprises, most with no borrowing experience. Hypothetical loan demand questions are used to test whether firm owners respond to changes in loans' contractual terms and whether take-up varies by firms' risk type and other firm owner characteristics. The results indicate that contracts with lower interest rates and less stringent collateral requirements attract less risky borrowers, suggesting that there is scope for improvement of standard financial contract terms. Credit Contract Structure and Firm Growth: Evidence from a Randomized Control Trial. We study the effects of credit contract structure on firm outcomes among small and medium sized firms. A randomized control trial was carried out to distinguish between some of the key constraints to efficient credit use connected to the firms' business environment and production function, namely (i) backloaded returns (ii) uncertain returns and (iii) indivisible fixed costs. Each firm was followed for the 1-year loan cycle. We describe the experiment and present preliminary results from the first 754 out of 2,340 firms to have completed the loan cycle. Firms offered a grace period have higher profits and higher household income than firms receiving a rebate later on as well as the control group. They also increased the number of paid employees and reduced the number of unpaid employees, an effect also found among firms that received a cash subsidy at the beginning of the loan cycle. We discuss potential mechanisms behind these effects.
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This paper investigates the simultaneous causal relationship between investments in information and communication technology (ICT) and flows of foreign direct investment (FDI), with reference to its implications on economic growth. For the empirical analysis we use data from 23 major countries with heterogeneous economic development for the period 1976-99. Our causality test results suggest that there is a causal relationship from ICT to FDI in developed countries, which means that a higher level of ICT investment leads to an increase inflow of FDI. ICT may contribute to economic growth indirectly by attracting more FDI. Contrarily, we could not find significant causality from ICT to FDI in developing countries. Instead, we have partial evidence of opposite causality relationship: the inflow of FDI causes further increases in ICT investment and production capacity. © United Nations University 2006.
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Purpose – This paper aims to contribute to the debate on the drivers of the productivity gap that exists between the UK and its major international competitors. Design/methodology/approach – From the macro perspective the paper explores the quantitative evidence on the productivity differentials and how they are measured. From the micro perspective, the article explores the quantitative evidence on the role of management practices claimed to be a key determinant in promoting firm competitiveness and in bridging the UK gap. Findings – This study suggests that management practices are an ambiguous driver of firm productivity and higher firm performance. On the methodological side, qualitative and subjective measures of either management practices or firm performance are often used. This makes the results not comparable across studies, across firms or even within firms over time. Productivity and profitability are often and erroneously interchangeably used while productivity is only one element of firm performance. On the other hand, management practices are multi-dimensional constructs that generally do not demonstrate a straightforward relationship with productivity variables. To assume that they are the only driver of higher productivity may be misleading. Moreover, there is evidence of an inverse causal relationship between management practices and firm performance. This calls into question most empirical results of the extant literature based on the unidirectional assumption of direct causality between management practices and firm performance. Research limitations/implications – These and other issues suggest that more research is needed to deepen the understanding of the UK productivity gap and more quantitative evidence should be provided on the way in which management practices contribute to the UK competitiveness. Their impact is not easily measurable due to their complexity and their complementary nature and this is a fertile ground for further research. Originality/value – This paper brings together the evidence on the UK productivity gap and its main drivers, provided by the economics, management and performance measurement literature. This issue scores very highly in the agenda of policy makers and academics and has important implications for practitioners interested in evaluating the impact of managerial best practices.