شاخص کیفیت زندگی برای برآورد تمایل اجتماعی به پرداخت هزینه برای ایمنی

The engineering and management of human safety is an important societal objective that includes extensive efforts by governments, both legislative and administrative, to enhance the health and safety of the public. Although the achievement of safety goals depend primarily on individuals and organizations responsible for safety, much support is drawn from expertise in diverse scientific and engineering disciplines. The activities range from structural safety (dams, tunnels, bridges to tall buildings) to safe operation of hazardous industrial installations (energy generation facilities, LNG terminals, petrochemical plants) to transportation systems (airline, rail, car safety) to technologies designed to minimize adverse impacts on the environment. All these activities are crucially concerned with risk: with the likelihood and the probable effects of various measures on life and health. We have developed a unified rationale and a clear basis for effective strategic management of risk across diverse sectors. Safety is an important objective in society but it is not the only one. The allocation of society's resources devoted to safety must be continually appraised in light of competing needs, because there is a limit on the resources that can be expended to extend life. The paper presents the Life Quality Index (LQI) as a tool for the assessment of risk reduction initiatives that would support the public interest and enhance safety and quality of life. The paper provides an intuitive reformulation of the LQI as equivalent to a valid utility function that is consistent with the principles of rational decision analysis. The LQI is further refined to consider the issues of discounting of life years, competing background risks, and population age and mortality distribution. The LQI is applied to quantify the societal willingness-to-pay, which is an acceptable level of public expenditure in exchange for a reduction in the risk of death that results in improved life-quality.

Risks can always be reduced but at some cost. However, demands for absolute safety, implying zero risk, can do more harm than good. If the costs of risk reduction are disproportionate to the benefits derived, then it diverts societal resources away from critical areas such as health care, education and social services that also enhance the quality of life. As aptly noted by Henry David Thoreau (1852): the cost of a thing is the amount of what I will call life which is required to be exchanged for it, immediately or in the long run. The need to strike a balance between the benefits of improved safety (i.e. life extension), risk (potential for loss of life) and cost of risk reduction (i.e. enhancement of quality of life) is compelling. The balancing of impacts on the quality of life and health against economic costs of risk reduction, although controversial, is an essential professional obligation. Our ability to “save lives” is finite and limited by our capacity to create wealth. Thus, the central problem in managing risk, in effect, translates into our ability to allocate a scarce resource wisely. Our work has been partly motivated by developments in Canada in the early 1990s and, in particular, the recommendation of the Government of Canada's Regulatory Policy which requires comprehensive social and economic impact analysis for setting regulatory standards [1]. The goals of the policy are to ensure that the benefits of regulatory interventions must clearly outweigh the costs to Canadians. This is as true for policies that relate to safety and risk reduction initiatives as they do for other areas of concern. When faced with risk, we are attempting to answer, intuitively, three related questions: (i) Is it safe? (ii) Is it a big and important risk? and if so, (iii) At what cost and level of effort would a life-saving proposition be worthwhile to reduce risk? In this context, we have proposed the use of the Life Quality Index (LQI), described elsewhere [2], as a tool for assessing the rationale and effectiveness of decisions affecting the management of risk to life, health and safety. Good risk management not only requires a strategy for selecting risks (separating the important and consequential from the trivial risks), but also a consistent framework of reasoning as described below. The Life Quality Index is a social indicator derived to reflect the expected length of life in good health and the quality of life enhanced by wealth. It rests on the premise that helping individuals achieve a long life in good health is a fundamental value and therefore, it is ethical and reasonable to pursue this as a primary objective for risk management. The Life Quality Index gives an account of how well that objective is being met. Risk control and mitigation initiatives that do not increase the chance of longer life in good health detract from that objective and their justification remains tenuous. The LQI can help us choose appropriate strategies for managing risk. Applications of LQI to safety of structures and other technical facilities have been illustrated in [3], [4] and [5]. The LQI combines societal wealth and longevity in the following function form: LQI=Gwe1−w, where G is the real gross domestic product ($/year/person), e is the life expectancy at birth, and w is a constant that reflects the proportion of time spent in producing G. In the original derivation, LQI was presented as a mathematical construct [2], which requires additional explanation and justification. It has been observed by researchers and critiques that there is no clear explanation as to how an LQI-based model satisfies basic principles of decision making. For example, implications of power functions Gw on societal preferences, the value of w, and the issue of discounting of cost and lives saved have not been discussed. Lack of a clear connection between the LQI and widely accepted principles of utility theory has been an impediment to wider acceptance of the LQI in cost-benefit analysis of risk reduction programs. In cost-benefit analysis of projects that requires treatment of safety in terms of lives “saved” or extended and monetary investments, the discounting of benefits of mortality reduction poses considerable challenge. The purpose of the paper is to provide a formulation of the LQI as equivalent to a valid utility function that is consistent with the principles of rational decision analysis. In addition, we develop an approach to quantify the societal willingness to pay (SWTP) for risk reduction initiatives. The proposed model is refined to consider the issues of discounting of life years and competing risks, and population age and mortality distribution. The next Section describes a unified foundation for risk management strategy in the form of four key principles. It also provides the supporting rationale for the use of social indicators in the management of health and safety risks. Section 3 describes the development of the Life-Quality Index and addresses issues related to its application to risk management. Section 4 illustrates application of LQI model to the estimation of societal willingness to pay in Canada. Main conclusions of the study are presented in Section 5. The original derivation of LQI, given in [2], is described again in the Appendix as a reference to the reader.

The LQI model is useful for judging the efficacy of regulatory standards for health, safety and the environment. The concept of life quality to enhance the basis of the cost-benefit analysis of programs involving risk to life is a significant new improvement. We have shown how to place the management of public risks into the broader context of social policy by presenting a unified foundation for risk management strategy in the form of four principles. Together these principles reflect the necessary general attributes of the good life in a modern state: public accountability, maximum net benefit for all, compensation for those who lose when there is change, and long life in good health with maximum personal choice. The paper presents a life-quality index (LQI) that gives the necessary criterion to determine the level of expenditure beyond which it is no longer justifiable to spend resources in the name of safety. It is referred to as “Societal Willingness to Pay” measure. A unified framework using life-quality as a basis for cost-benefit analysis is the primary contribution of the paper. The approach incorporates important issues and concepts in public policy analysis, namely, discounting of life years, competing mortality risks, inter-temporal tradeoffs, and age-dependent risk and willingness to pay. The significant aspect is that integration of these issues is done in a consistent and transparent manner to support a credible analysis. In this respect, the proposed approach provides an improved approach to the valuation of mortality.