Using decision science to gain insight into ethical issues: an example involving thresholds in workers' compensation.

Systematically analyzing and comparing the ethical dimensions of policy-decision alternatives is remarkably difficult. The ethical implications of a set of decision alternatives, as well as the ranking of that set, are subject to any number of quantitative and qualitative variables, not the least of which is differing individual interpretation. In spite of this, decision science offers a consistent, transparent framework from which to analyze the ethical components and implications of policy decisions. Workers' Compensation insurance programs are state-governed systems of insurance in which workers, in exchange for giving up the right to sue their employer and their coemployees, receive some compensation if they are injured on the job, without regard as to who was at fault. Importantly, Workers' Compensation does not compensate workers for all losses. Thus, injured workers often sue those who provide goods and services to their employer's production system. Different states set different thresholds relating to who can be brought into such a lawsuit and under what conditions a sued means-of-production entity can, in turn, bring the injured party's employer into the suit as a third-party defendant. Forensic engineers are often involved in such lawsuits to evaluate whether or not a given component of a production system is or is not defective. Using Workers' Compensation as an example, this paper explores the methodology and the difficulty of quantifying the ethical implications of policy decisions by examining the concept of thresholding a policy variable. Thresholding will be defined and the ethical effect on the various parties of varying a policy threshold will be discussed.

Biomechanics of slips.

The biomechanics of slips are an important component in the prevention of fall-related injuries. The purpose of this paper is to review the available literature on the biomechanics of gait relevant to slips. This knowledge can be used to develop slip resistance testing methodologies and to determine critical differences in human behaviour between slips leading to recovery and those resulting in falls. Ground reaction forces at the shoe-floor interface have been extensively studied and are probably the most critical biomechanical factor in slips. The ratio of the shear to normal foot forces generated during gait, known as the required coefficient of friction (RCOF) during normal locomotion on dry surfaces or 'friction used/achievable' during slips, has been one biomechanical variable most closely associated with the measured frictional properties of the shoe/floor interface (usually the coefficient of friction or COF). Other biomechanical factors that also play an important role are the kinematics of the foot at heel contact and human responses to slipping perturbations, often evident in the moments generated at the lower extremity joints and postural adaptations. In addition, it must be realized that the biomechanics are dependent upon the capabilities of the postural control system, the mental set of the individual, and the perception of the environment, particularly, the danger of slipping. The focus of this paper is to review what is known regarding the kinematics and kinetics of walking on surfaces under a variety of environmental conditions. Finally, we discuss future biomechanical research needs to help to improve walkway-friction measurements and safety.