On the Limits of the Precautionary Principle

The precautionary principle (PP) is an influential principle of risk management. It has been widely introduced into environmental legislation, and it plays an important role in most international environmental agreements. Yet, there is little consensus on precisely how to understand and formulate the principle. In this article I prove some impossibility results for two plausible formulations of the PP as a decision‐rule. These results illustrate the difficulty in making the PP consistent with the acceptance of any tradeoffs between catastrophic risks and more ordinary goods. How one interprets these results will, however, depend on one's views and commitments. For instance, those who are convinced that the conditions in the impossibility results are requirements of rationality may see these results as undermining the rationality of the PP. But others may simply take these results to identify a set of purported rationality conditions that defenders of the PP should not accept, or to illustrate types of situations in which the principle should not be applied.     

The Limits of Catastrophe Aversion

We discuss the management of catastrophe-risks from a theoretical point of view. The concept of a catastrophe is informally and formally defined, and a number of desiderata for catastrophe-averse decision rules are introduced. However, the proposed desiderata turn out to be mutually inconsistent. As a consequence of this result, it is argued that the "rigid" form of catastrophe aversion articulated by, for example, the maximin rule, the maximum probable loss rule, (some versions of) the precautionary principle, and the rule proposed in Ekenberg et al. (1997, 2000) should be given up. An alternative form of "non-rigid" catastrophe aversion is considered.     

Is the Precautionary Principle Really Incoherent?

The Precautionary Principle has been an increasingly important principle in international treaties since the 1980s. Through varying formulations, it states that when an activity can lead to a catastrophe for human health or the environment, measures should be taken to prevent it even if the cause‐and‐effect relationship is not fully established scientifically. The Precautionary Principle has been critically discussed from many sides. This article concentrates on a theoretical argument by Peterson (2006) according to which the Precautionary Principle is incoherent with other desiderata of rational decision making, and thus cannot be used as a decision rule that selects an action among several ones. I claim here that Peterson's argument fails to establish the incoherence of the Precautionary Principle, by attacking three of its premises. I argue (i) that Peterson's treatment of uncertainties lacks generality, (ii) that his Archimedian condition is problematic for incommensurability reasons, and (iii) that his explication of the Precautionary Principle is not adequate. This leads me to conjecture that the Precautionary Principle can be envisaged as a coherent decision rule, again.     

Risk Analysis, Life Cycle Assessment—The Common Challenge of Dealing with the Precautionary Frame (Based on the Toxicity Controversy in Sweden and the Netherlands)

Life cycle impact assessment (LCIA) and comparative risk assessment (RA) use the same building blocks for analyzing fate and potential effects of toxic substances. It is tacitly assumed that emission-effect calculations can give uniform and decisive answers in debates on toxicity problems. For several decades, mainstream policy sciences have taken a different starting point when analyzing decision making on complex, controversial societal issues. Such controversies in essence are thought to be caused by the fact that different actor coalitions adhere to a different, but in scientific terms equally reasonable, conceptualization or "framing" of the problem. A historical, argumentative analysis of the Dutch chlorine debate and the Swedish PVC debate shows that this is also true in the discussions on toxic substances. Three frames have been identified, which were coined the "risk assessment frame," "the strict control frame," and the "precautionary frame." These frames tacitly disagree about the extent of knowledge/ignorance about the impacts of substances, the robustness/fallibility of emission-reduction schemes, and the robustness/vulnerability of nature. The latter frame, adhered to by environmentalists, seeks to judge substances mainly on their inherent safety. Under the current institutional arrangements and practices, RA and LCIA are executed mainly in line with the philosophy expressed by the risk assessment frame. This article gives various suggestions for dealing with framing in debates on toxic substances. One of the options is elaborated in somewhat more detail, i.e., the development of multiple indicators and calculation schemes for RA and LCIA that reflect the different frames. An outline is given for a possible indicator system reflecting the precautionary principle.     

The Precautionary Principle and/or Risk Assessment in World Trade Organization Decisions: A Possible Role for Risk Perception

Risk analysis has been recognized and validated in World Trade Organization (WTO) decision processes. In recent years the precautionary principle has been proposed as an additional or alternative approach to standard risk assessment. The precautionary principle has also been advocated by some who see it as part of postmodern democracy in which more power is given to the public on health and safety matters relative to the judgments of technocrats. A more cynical view is that the precautionary principle is particularly championed by the European Community as a means to erect trade barriers. The WTO ruling against the European Community's trade barrier against beef from hormone-treated cattle seemed to support the use of risk assessment and appeared to reject the argument that the precautionary principle was a legitimate basis for trade barriers. However, a more recent WTO decision on asbestos contains language suggesting that the precautionary principle, in the form of taking into account public perception, may be acceptable as a basis for a trade barrier. This decision, if followed in future WTO trade disputes, such as for genetically modified foods, raises many issues central to the field of risk analysis. It is too early to tell whether the precautionary principle will become accepted in WTO decisions, either as a supplement or a substitute for standard risk assessment. But it would undermine the value of the precautionary principle if this principle were misused to justify unwarranted trade barriers.     

Managing the Risk of Uncertain Threshold Responses: Comparison of Robust, Optimum, and Precautionary Approaches

Many commentators have suggested the need for new decision analysis approaches to better manage systems with deeply uncertain, poorly characterized risks. Most notably, policy challenges such as abrupt climate change involve potential nonlinear or threshold responses where both the triggering level and subsequent system response are poorly understood. This study uses a simple computer simulation model to compare several alternative frameworks for decision making under uncertainty -- optimal expected utility, the precautionary principle, and three different approaches to robust decision making -- for addressing the challenge of adding pollution to a lake without triggering unwanted and potentially irreversible eutrophication. The three robust decision approaches -- trading some optimal performance for less sensitivity to assumptions, satisficing over a wide range of futures, and keeping options open -- are found to identify similar strategies as the most robust choice. This study also suggests that these robust decision approaches offer a quantitative, decision analytic framework that captures the spirit of the precautionary principle while addressing some of its shortcomings. Finally, this study finds that robust strategies may be preferable to optimum strategies when the uncertainty is sufficiently deep and the set of alternative policy options is sufficiently rich.     

The Precautionary Principle Versus Risk Analysis

Precautionary behavior serves a valuable protective purpose as a first response to the new. It causes a quick retreat to the safety of the familiar; it provides time for a realistic "friend or foe" assessment of a new event. This rational assessment is often delayed by the sluggishness of government bureaucratic processes, or stopped by an implied challenge to a status quo. At the public level, reassurance may be slow to overcome an early uncertainty. However, a precautionary response does not provide an operational governing principle, although it makes publicly plausible an indefinite concealment of de facto political actions, or nonaction. The alternative of rational decision making at the policy level should flow from a comparative benefit/cost/risk analysis. Such early risk analyses have pragmatic uncertainties based on the limited available knowledge base and, accordingly, require judgmental application.     

The 1991 Cholera Epidemic in Peru: Not a Case of Precaution Gone Awry

The precautionary principle calls on decisionmakers to take preventive action in light of evidence indicating that there is a potential for harm to public health and the environment, even though the nature and magnitude of harm are not fully understood scientifically. Critics of the precautionary principle frequently argue that unbridled application of the principle leads to unintended damage to health and ecosystems (risk tradeoffs) and that precautious decision making leaves us vulnerable to "false-positive" risks that divert resources away from "real risks." The 1991 cholera epidemic in Peru is often cited as an example of these pitfalls of the precautionary principle. It has been mistakenly argued that application of the precautionary principle caused decisionmakers to stop chlorinating the water supply due to the risks of disinfection byproducts (DBPs), resulting in the epidemic. Through analyses of investigations conducted in the cities of Iquitos and Trujillo, Peru, literature review, and interviews with leading Peruvian infectious disease researchers, we determined that the epidemic was caused by a much more complex set of circumstances, including poor sanitation conditions, poor separation of water and waste streams, and inadequate water treatment and distribution systems. The evidence indicates that no decision was made to stop chlorinating on the basis of DBP concerns and that concerns raised about DBPs masked more important factors limiting expansion of chlorination. In fact, outside of Peru's capital Lima, chlorination of drinking water supplies at the time of the epidemic was limited at best. We conclude that the Peruvian cholera epidemic was not caused by a failure of precaution but rather by an inadequate public health infrastructure unable to control a known risk: that of microbial contamination of water supplies.     

Building Blocks for a Precautionary Approach to the Use of Nanomaterials: Positions Taken by Trade Unions and Environmental NGOs in the European Nanotechnologies Debate

As partners in the European capacity‐building project NanoCap, trade unions and environmental nongovernmental organizations (NGOs) have established positions on the development of nanotechnologies. Key in their positioning is their view that the use of nanomaterials with currently unknown occupational and environmental hazards must have consequences for the risk management and use of nanoproducts. They have made proposals for responsible manufacturing and for applying the precautionary principle to the use of nanoproducts and they urgently call for the acceptance and the operationalization of a precautionary approach by the industry and governments. The trade unions and NGOs are calling for transparency and openness regarding processes and products that contain nanomaterials and have proposed specific tools for nanomaterial use that put the precautionary principle into practice, including the principles no data → no exposure and no data → no emission. The proposed tools also include compulsory reporting of the type and content of nanoparticles applied in products, a register of workers possibly exposed to nanoparticles, and the use of nano reference values as guides to assess workplace exposure to nanoparticles.     

Yes,The Precautionary Principle Is Incoherent

This article is a reply to Thomas Boyer‐Kassem's discussion of my criticism of the precautionary principle published in this journal about a decade ago. Boyer‐Kassem does not question the logical validity of the theorem proved in my original article, but he brings up important questions about its scope. He also challenges the plausibility of some of the assumptions on which it is based. In this comment, I argue that each objection can be adequately dealt with. As a decision rule, the precautionary principle is (still) incoherent.     

Measuring Christian Beliefs that Affect Managerial Decision-Making: A Beginning

Although considerable work has been done on the measurement of religious values and beliefs, little is understood about their effect on managerial values and decision making. This paper reports on theoretical work by the authors identifying Christian religious beliefs that might affect managerial decision making; it also reports the results of empirical work validating five scales of religious beliefs that might affect managerial decision making. Future research directions are proposed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Community Resilience and Decision Theory Challenges for Catastrophic Events

Extreme and catastrophic events pose challenges for normative models of risk management decision making. They invite development of new methods and principles to complement existing normative decision and risk analysis. Because such events are rare, it is difficult to learn about them from experience. They can prompt both too little concern before the fact, and too much after. Emotionally charged and vivid outcomes promote probability neglect and distort risk perceptions. Aversion to acting on uncertain probabilities saps precautionary action; moral hazard distorts incentives to take care; imperfect learning and social adaptation (e.g., herd‐following, group‐think) complicate forecasting and coordination of individual behaviors and undermine prediction, preparation, and insurance of catastrophic events. Such difficulties raise substantial challenges for normative decision theories prescribing how catastrophe risks should be managed. This article summarizes challenges for catastrophic hazards with uncertain or unpredictable frequencies and severities, hard‐to‐envision and incompletely described decision alternatives and consequences, and individual responses that influence each other. Conceptual models and examples clarify where and why new methods are needed to complement traditional normative decision theories for individuals and groups. For example, prospective and retrospective preferences for risk management alternatives may conflict; procedures for combining individual beliefs or preferences can produce collective decisions that no one favors; and individual choices or behaviors in preparing for possible disasters may have no equilibrium. Recent ideas for building “disaster‐resilient” communities can complement traditional normative decision theories, helping to meet the practical need for better ways to manage risks of extreme and catastrophic events.     

The Precautionary Principle Has Not Been Shown to Be Incoherent: A Reply to Peterson

In this journal, I have objected to Peterson's 2006 claim that the precautionary principle is an incoherent decision rule. I defend my objections to Peterson's recent replies, and I still claim that the precautionary principle has not been shown to be incoherent.     

Categorizing Mistaken False Positives in Regulation of Human and Environmental Health

One of the concerns often voiced by critics of the precautionary principle is that a widespread regulatory application of the principle will lead to a large number of false positives (i.e., over-regulation of minor risks and regulation of nonexisting risks). The present article proposes a general definition of a regulatory false positive, and seeks to identify case studies that can be considered authentic regulatory false positives. Through a comprehensive review of the science policy literature for proclaimed false positives and interviews with authorities on regulation and the precautionary principle we identified 88 cases. Following a detailed analysis of these cases, we found that few of the cases mentioned in the literature can be considered to be authentic false positives. As a result, we have developed a number of different categories for these cases of "mistaken false positives," including: real risks, "The jury is still out," nonregulated proclaimed risks, "Too narrow a definition of risk," and risk-risk tradeoffs. These categories are defined and examples are presented in order to illustrate their key characteristics. On the basis of our analysis, we were able to identify only four cases that could be defined as regulatory false positives in the light of today's knowledge and recognized uncertainty: the Southern Corn Leaf Blight, the Swine Flu, Saccharin, and Food Irradiation in relation to consumer health. We conclude that concerns about false positives do not represent a reasonable argument against future application of the precautionary principle.     

Against the De Minimis Principle

According to the class of de minimis decision principles, risks can be ignored (or at least treated very differently from other risks) if the risk is sufficiently small. In this article, we argue that a de minimis threshold has no place in a normative theory of decision making, because the application of the principle will either recommend ignoring risks that should not be ignored (e.g., the sure death of a person) or it cannot be used by ordinary bounded and information-constrained agents.     

Risk Management and the Precautionary Principle: A Fuzzy Logic Model

The aim of this article is to illustrate a procedure for applying the precautionary principle within a strategy for reducing the possibility of underestimating the effective risk caused by a phenomenon, product, or process, and of adopting insufficient risk reduction measures or overlooking their need. We start by simply defining risk as the product between the numerical expression of the adverse consequences of an event and the likelihood of its occurrence or the likelihood that such consequences will occur. Uncertainty in likelihood estimates and several key concepts inherent to the precautionary principle, such as sufficient certainty, prevention, and desired level of protection, are represented as fuzzy sets. The strategy described may be viewed as a simplified example of a precautionary decision process that has been chiefly conceived as a theoretical contribution to the debate concerning the precautionary principle, the quantification of its application, and the formal approach to such problems.     

Trade-offs and the precautionary principle: A lexicographic utility approach

The precautionary principle is often argued to be irrational because it cannot adequately explain how resources should be distributed across multiple possible catastrophes or between catastrophic and noncatastrophic risks. We address this problem of trade-offs by extending a recently proposed formal interpretation of the precautionary principle (PP) within a lexical utility framework and using it to prove results about which distribution of resources maximizes lexical utility when several catastrophic risks exist, given different assumptions. We also explain how our lexical utility interpretation of PP can recommend balanced distributions of resources between disaster prevention and other concerns.     

基于DEA联盟博弈核仁解的固定成本分摊方法研究

本文结合DEA(Data Envelopment Analysis)和联盟博弈理论研究了固定成本分摊问题.本文首先证明了在固定成本作为决策单元(Decision Making Unit,DMU)新投入要素的条件下,那么DMU个体和整体将同为DEA有效,在此结论的基础上,本文结合联盟博弈理论,定义了联盟博弈的特征函数,提出了基于核仁解的固定成本分摊模型,并给出了相应的求解算法,最终通过算例说明了本文方法的合理性和求解算法的可行性.     

Objective and Subjective Rationality in a Multiple Prior Model

A decision maker (DM) is characterized by two binary relations. The first reflects choices that are rational in an “objective” sense: the DM can convince others that she is right in making them. The second relation models choices that are rational in a “subjective” sense: the DM cannot be convinced that she is wrong in making them. In the context of decision under uncertainty, we propose axioms that the two notions of rationality might satisfy. These axioms allow a joint representation by a single set of prior probabilities and a single utility index. It is “objectively rational” to choose f in the presence of g if and only if the expected utility of f is at least as high as that of g given each and every prior in the set. It is “subjectively rational” to choose f rather than g if and only if the minimal expected utility of f (with respect to all priors in the set) is at least as high as that of g. In other words, the objective and subjective rationality relations admit, respectively, a representation à la Bewley (2002) and à la Gilboa and Schmeidler (1989). Our results thus provide a bridge between these two classic models, as well as a novel foundation for the latter.     

Intergenerational Risk Decision Making: A Practical Example

There is no such thing as intergenerational decision making, at least not yet. In fact, there is no such thing as intragenerational decision making in the context of maximizing overall social good given resource limitations, there are just decisions being made in an ad hoc fashion. Even if one assumes that there is such a thing as intragenerational decision making, no uniform standard or guidance exists to make societal decisions for the common good. Risks to society are judged unevenly within the same agency and across agencies. Decisions are made in isolation and not weighed in the societal context of what is intra or intergenerationally important. The National Academy of Public Administration (NAPA) has set forth a framework for intergenerational decision making that provides a consistent and fair basis for making tough decisions in order to address difficult issues such as the long-term disposal of nuclear wastes. NAPA recognizes that there is an intergenerational obligation that must encompass broader questions than the narrow issue of waste disposal since resources are finite and needs are great. The fundamental principles are based on sustainability with the overarching objective that "no generation should needlessly, now or in the future, deprive its successors of the opportunity to enjoy a quality of life equivalent to its own." Coupled with this objective are four supporting principles of trusteeship, sustainability, chain of obligation, and precaution. The NAPA process also recognizes that no decision can be final and that a "rolling future" view is better than making decisions for "all time." It attempts to balance the needs of the present with those of the future in an open and transparent process that is aimed at producing a decision, not just endless analysis. The U.S. Congress and president should develop a rational standard by which to judge laws that involve intra and intergenerational issues relative to the overall societal good. Present regulations need to be evaluated relative to a uniform level of risk and benefit to assess where the limited money available can do the most good for both the present and future generations in the context of NAPA sustainability principles. It is hoped that decision makers will take a serious look at this process since it can work to resolve stakeholder stalemate.