Causality and Association: The Statistical and Legal Approaches

This paper discusses different needs and approaches to establishing ``causation'' that are relevant in legal cases involving statistical input based on epidemiological (or more generally observational or population-based) information. We distinguish between three versions of ``cause'': the first involves negligence in providing or allowing exposure, the second involves ``cause'' as it is shown through a scientifically proved increased risk of an outcome from the exposure in a population, and the third considers ``cause'' as it might apply to an individual plaintiff based on the first two. The population-oriented ``cause'' is that commonly addressed by statisticians, and we propose a variation on the Bradford Hill approach to testing such causality in an observational framework, and discuss how such a systematic series of tests might be considered in a legal context. We review some current legal approaches to using probabilistic statements, and link these with the scientific methodology as developed here. In particular, we provide an approach both to the idea of individual outcomes being caused on a balance of probabilities, and to the idea of material contribution to such outcomes. Statistical terminology and legal usage of terms such as ``proof on the balance of probabilities'' or ``causation'' can easily become confused, largely due to similar language describing dissimilar concepts; we conclude, however, that a careful analysis can identify and separate those areas in which a legal decision alone is required and those areas in which scientific approaches are useful.Comment: Published in at http://dx.doi.org/10.1214/07-STS234 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Energy Efficiency in Manufacturing Facilities: Assessment, Analysis and Implementation

Manufacturing facilities are one among the largest consumers of energy. Efforts to improve energy efficiency are an increasing concern for many manufacturing facility engineering managers. This can be achieved by evaluating energy end uses (e.g., lighting, processing equipment, and heating, air conditioning, and ventilation (HVAC) systems), and by implementing measures to reduce the total amount of energy consumed for one or more of the end uses. Throughout the 40 years of its existence, the US Department of Energy’s Industrial Assessment Center program has developed an array of techniques to improve energy efficiency in industrial facilities. This chapter discusses recommended assessment procedures and observed energy-saving opportunities for some of the most common industrial energy systems. These systems include lighting, compressed air, boilers and steam systems, manufacturing process heating, HVAC, pumps, and fans. Implementation of these assessment recommendations has been demonstrated to increase efficiency and to thus reduce energy consumption and associated costs. While every manufacturing facility is different, and their component industrial energy systems equally unique, this chapter presents a set of analytical guidelines that can be used as a template by engineering practitioners to evaluate their facility energy use and implement subsequent energy conservation measures

Heat capacity at the glass transition

A fundamental problem of glass transition is to explain the jump of heat capacity at the glass transition temperature $T_g$ without asserting the existence of a distinct solid glass phase. This problem is also common to other disordered systems, including spin glasses. We propose that if $T_g$ is defined as the temperature at which the liquid stops relaxing at the experimental time scale, the jump of heat capacity at $T_g$ follows as a necessary consequence due to the change of system's elastic, vibrational and thermal properties. In this picture, we discuss time-dependent effects of glass transition, and identify three distinct regimes of relaxation. Our approach explains widely observed logarithmic increase of $T_g$ with the quench rate and the correlation of heat capacity jump with liquid fragility

Internal Friction and Vulnerability of Mixed Alkali Glasses

Based on a hopping model we show how the mixed alkali effect in glasses can be understood if only a small fraction c_V ofthe available sites for the mobile ions is vacant. In particular, we reproduce the peculiar behavior of the internal friction and the steep fall (''vulnerability'') of the mobility of the majority ion upon small replacements by the minority ion. The single and mixed alkali internal friction peaks are caused by ion-vacancy and ion-ion exchange processes. If c_V is small, they can become comparable in height even at small mixing ratios. The large vulnerability is explained by a trapping of vacancies induced by the minority ions. Reasonable choices of model parameters yield typical behaviors found in experiments.Comment: 4 pages, 4 figure

How Do We Know If It Works? Measuring Outcomes in Bystander-Focused Abuse Prevention on Campuses

Objective: To address acknowledged limitations in the effectiveness of sexual and relationship abuse prevention strategies, practitioners have developed new tools that use a bystander framework (Lonsway et al, 2009). Evaluation of bystander-focused prevention requires measures, specific to the bystander approach, that assess changes over time in participants’ attitudes and behaviors. Few measures exist and more psychometric analyses are needed. We present analyses to begin to establish the psychometric properties of four new measures of bystander outcomes and their subscales. Method: We collected data from 948 first year college students on two campuses in the northeast United States. Items assessing attitudes and behaviors related to bystander helping responses in college campus communities for situations where there is sexual or relationship abuse risk were factor analyzed. Results: Measures of readiness to help (assessed specifically with scales representing taking action, awareness, and taking responsibility), intent to be an active bystander, self-reported bystander responses, and perceptions of peer norms in support of action all showed adequate reliability and validity. Conclusion: The study represents a next step in the development of tools that can be used by researchers and practitioners seeking both to understand bystander behavior in the context of sexual and relationship abuse and evaluating the effectiveness of prevention tools to address these problems. The measures investigated will be helpful for prevention educators and researchers evaluating the effectiveness of sexual and relationship abuse education tools that use a bystander intervention framework