Clarifying Types of Uncertainty: When Are Models Accurate,and Uncertainties Small?

Professor Aven has recently noted the importance of clarifying the meaning of terms such as "scientific uncertainty" for use in risk management and policy decisions, such as when to trigger application of the precautionary principle. This comment examines some fundamental conceptual challenges for efforts to define "accurate" models and "small" input uncertainties by showing that increasing uncertainty in model inputs may reduce uncertainty in model outputs; that even correct models with "small" input uncertainties need not yield accurate or useful predictions for quantities of interest in risk management (such as the duration of an epidemic); and that accurate predictive models need not be accurate causal models.     

Multi‐Case Review of the Application of the Precautionary Principle in European Union Law and Case Law

The precautionary principle was formulated to provide a basis for political action to protect the environment from potentially severe or irreversible harm in circumstances of scientific uncertainty that prevent a full risk or cost‐benefit analysis. It underpins environmental law in the European Union and has been extended to include public health and consumer safety. The aim of this study was to examine how the precautionary principle has been interpreted and subsequently applied in practice, whether these applications were consistent, and whether they followed the guidance from the Commission. A review of the literature was used to develop a framework for analysis, based on three attributes: severity of potential harm, standard of evidence (or degree of uncertainty), and nature of the regulatory action. This was used to examine 15 pieces of legislation or judicial decisions. The decision whether or not to apply the precautionary principle appears to be poorly defined, with ambiguities inherent in determining what level of uncertainty and significance of hazard justifies invoking it. The cases reviewed suggest that the Commission's guidance was not followed consistently in forming legislation, although judicial decisions tended to be more consistent and to follow the guidance by requiring plausible evidence of potential hazard in order to invoke precaution.     

Anticipating or Accommodating to Public Concern? Risk Amplification and the Politics of Precaution Reexamined

Regulatory use of the precautionary principle (PP) tends to be broadly characterized either as a responsible approach for safeguarding against health and environmental risks in the face of scientific uncertainties, or as “state mismanagement” driven by undue political bias and public anxiety. However, the “anticipatory” basis upon which governments variably draw a political warrant for adopting precautionary measures often remains ambiguous. Particularly, questions arise concerning whether the PP is employed preemptively by political elites from the “top down,” or follows from more conventional democratic pressures exerted by citizens and other stakeholders from the “bottom up.” This article elucidates the role and impact of citizen involvement in the precautionary politics shaping policy discourse surrounding the U.K. government's “precautionary approach” to mobile telecommunications technology and health. A case study is presented that critically reexamines the basis upon which U.K. government action has been portrayed as an instance of anticipatory policy making. Findings demonstrate that the use of the PP should not be interpreted in the preemptive terms communicated by U.K. government officials alone, but also in relation to the wider social context of risk amplification and images of public concern formed adaptively in antagonistic precautionary discourse between citizens, politicians, industry, and the media, which surrounded cycles of government policy making. The article discusses the sociocultural conditions and political dynamics underpinning public influence on government anticipation and responsiveness exemplified in this case, and concludes with research and policy implications for how society subsequently comes to terms with the emergence and precautionary governance of new technologies under conflict.     

A new approach to risk evaluation and management: risk-based, precaution-based, and discourse-based strategies.

Our concept of nine risk evaluation criteria, six risk classes, a decision tree, and three management categories was developed to improve the effectiveness, efficiency, and political feasibility of risk management procedures. The main task of risk evaluation and management is to develop adequate tools for dealing with the problems of complexity, uncertainty. and ambiguity. Based on the characteristics of different risk types and these three major problems, we distinguished three types of management--risk-based, precaution-based, and discourse-based strategies. The risk-based strategy--is the common solution to risk problems. Once the probabilities and their corresponding damage potentials are calculated, risk managers are required to set priorities according to the severity of the risk, which may be operationalized as a linear combination of damage and probability or as a weighted combination thereof. Within our new risk classification, the two central components have been augmented with other physical and social criteria that still demand risk-based strategies as long as uncertainty is low and ambiguity absent. Risk-based strategies are best solutions to problems of complexity and some components of uncertainty, for example, variation among individuals. If the two most important risk criteria, probability of occurrence and extent of damage, are relatively well known and little uncertainty is left, the traditional risk-based approach seems reasonable. If uncertainty plays a large role, in particular, indeterminacy or lack of knowledge, the risk-based approach becomes counterproductive. Judging the relative severity of risks on the basis of uncertain parameters does not make much sense. Under these circumstances, management strategies belonging to the precautionary management style are required. The precautionary approach has been the basis for much of the European environmental and health protection legislation and regulation. Our own approach to risk management has been guided by the proposition that any conceptualization of the precautionary principle should be (1) in line with established methods of scientific risk assessments, (2) consistent and discriminatory (avoiding arbitrary results) when it comes to prioritization, and (3) at the same time, specific with respect to precautionary measures, such as ALARA or BACT, or the strategy of containing risks in time and space. This suggestion does, however, entail a major problem: looking only to the uncertainties does not provide risk managers with a clue about where to set priorities for risk reduction. Risks vary in their degree of remaining uncertainties. How can one judge the severity of a situation when the potential damage and its probability are unknown or contested? In this dilemma, we advise risk managers to use additional criteria of hazardousness, such as "ubiquity versibility," and "pervasiveness over time," as proxies for judging severity. Our approach also distinguishes clearly between uncertainty and ambiguity. Uncertainty refers to a situation of being unclear about factual statements; ambiguity to a situation of contested views about the desirability or severity of a given hazard. Uncertainty can be resolved in principle by more cognitive advances (with the exception of indeterminacy). ambiguity only by discourse. Discursive procedures include legal deliberations as well as novel participatory approaches. In addition, discursive methods of planning and conflict resolution can be used. If ambiguities are associated with a risk problem, it is not enough to demonstrate that risk regulators are open to public concerns and address the issues that many people wish them to take care ot The process of risk evaluation itself needs to be open to public input and new forms of deliberation. We have recommended a tested set of deliberative processes that are, at least in principle, capable of resolving ambiguities in risk debates (for a review, see Renn, Webler, & Wiedemaun. 1995). Deliberative processes are needed, however, for ail three types of management. Risk-based management relies on epistemiological, uncertainty-based management on reflective, and discourse-based management on participatory discourse forms. These three types of discourse could be labeled as an analytic-deliberative procedure for risk evaluation and management. We see the advantage of a deliberative style of regulation and management in a dynamic balance between procedure and outcome. Procedure should not have priority over the outcome; outcome should not have priority over the procedure. An intelligent combination of both can elaborate the required prerequisites of democratic deliberation and its substantial outcomes to enhance the legitimacy of political decisions (Guttman & Thompson, 1996; Bohman, 1997. 1998).     

On the Meaning and Use of the Risk Appetite Concept

The risk appetite concept has been given considerable attention recently in enterprise risk management contexts. A number of definitions exist, most with a link to risk acceptability, but also values and goals. The usefulness of the concept is, however, disputed; some authors argue that we can in fact do better without it. In this article, we provide a thorough discussion of what the risk appetite concept is actually trying to express and how it best can be used in the relevant decision making. The main purposes of the article are (i) to argue that the risk appetite concept, suitably interpreted, has a role to play in risk management, (ii) to show that the risk appetite concept is well supported by some types of risk perspectives and not by others, and (iii) to show how the risk appetite concept is linked to other related concepts, such as risk seeking and risk acceptability. The risk perspectives studied range from expected value and probability based definitions of risk to views on risk, that are founded on uncertainties.     

Application of the Precautionary Principle by Senior Policy Officials: Results of a Canadian Survey

Though use of the controversial precautionary principle in risk management has increasingly been recommended as a guide for the construction of public policy in Canada and elsewhere, there are few data available characterizing its use in risk management by senior public policymakers. Using established survey methodology we sought to investigate the perceptions and terms of application of the precautionary principle in this important subset of individuals. A total of 240 surveys were sent out to seven departments or agencies in the Canadian government. The overall survey response rate was 26.6%, and our findings need to be interpreted in the context of possible responder bias. Of respondents, the overwhelming majority perceived the precautionary principle and the management of risk as complementary, and endorsed a role for the precautionary principle as a general guideline for all risk management decisions. However, 25% of respondents responded that the lack of clarity of the definition of the principle was a limitation to its effective use. The majority of respondents viewed their own level of understanding of the precautionary principle as moderate. Risk managers appeared to favor an interpretation of the precautionary principle that was based on the seriousness and irreversibility of the threat of damage, and did not endorse as strongly the need for cost effectiveness in the measures taken as a precaution against such threats. In contrast with its perceived role as a general guideline, the application of the precautionary principle by respondents was highly variable, with >60% of respondents reporting using the precautionary principle in one-quarter or less of all risk management decisions. Several factors influenced whether the precautionary principle was applied with the perceived seriousness of the threat being considered the most influential factor. The overwhelming majority of risk managers felt that "preponderance of evidence" was the level of evidence required for precautionary action to be instituted against a serious negative event. Overall, the majority of respondents viewed the precautionary principle as having a significant and positive impact on risk management decisions. Importantly, respondents endorsed a net result of more good than harm to society when the precautionary principle was applied to the management of risk.     

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.     

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.     

Communicating Earthquake Preparedness: The Influence of Induced Mood,Perceived Risk,and Gain or Loss Frames on Homeowners’ Attitudes Toward General Precautionary Measures for Earthquakes

Despite global efforts to reduce seismic risk, actual preparedness levels remain universally low. Although earthquake‐resistant building design is the most efficient way to decrease potential losses, its application is not a legal requirement across all earthquake‐prone countries and even if, often not strictly enforced. Risk communication encouraging homeowners to take precautionary measures is therefore an important means to enhance a country's earthquake resilience. Our study illustrates that specific interactions of mood, perceived risk, and frame type significantly affect homeowners’ attitudes toward general precautionary measures for earthquakes. The interdependencies of the variables mood, risk information, and frame type were tested in an experimental 2 × 2 × 2 design (N = 156). Only in combination and not on their own, these variables effectively influence attitudes toward general precautionary measures for earthquakes. The control variables gender, “trait anxiety” index, and alteration of perceived risk adjust the effect. Overall, the group with the strongest attitudes toward general precautionary actions for earthquakes are homeowners with induced negative mood who process high‐risk information and gain‐framed messages. However, the conditions comprising induced negative mood, low‐risk information and loss‐frame and induced positive mood, low‐risk information and gain‐framed messages both also significantly influence homeowners’ attitudes toward general precautionary measures for earthquakes. These results mostly confirm previous findings in the field of health communication. For practitioners, our study emphasizes that carefully compiled communication measures are a powerful means to encourage precautionary attitudes among homeowners, especially for those with an elevated perceived risk.     

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.     

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 Is Incoherent

This article argues that no version of the precautionary principle can be reasonably applied to decisions that may lead to fatal outcomes. In support of this strong claim, a number of desiderata are proposed, which reasonable rules for rational decision making ought to satisfy. Thereafter, two impossibility theorems are proved, showing that no version of the precautionary principle can satisfy the proposed desiderata. These theorems are directly applicable to recent discussions of the precautionary principle in medicine, biotechnology, environmental management, and related fields. The impossibility theorems do not imply, however, that the precautionary principle is of no relevance at all in policy discussions. Even if it is not a reasonable rule for rational decision making, it is possible to interpret the precautionary principle in other ways, e.g., as an argumentative tool or as an epistemic principle favoring a reversed burden of proof.     

Modeling Correlated Discrete Uncertainties in Event Trees with Copulas

Modeling the dependence between uncertainties in decision and risk analyses is an important part of the problem structuring process. We focus on situations where correlated uncertainties are discrete, and extend the concept of the copula‐based approach for modeling correlated continuous uncertainties to the representation of correlated discrete uncertainties. This approach reduces the required number of probability assessments significantly compared to approaches requiring direct estimates of conditional probabilities. It also allows the use of multiple dependence measures, including product moment correlation, rank order correlation and tail dependence, and parametric families of copulas such as normal copulas, t‐copulas, and Archimedean copulas. This approach can be extended to model the dependence between discrete and continuous uncertainties in the same event tree.     

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.     

Analyzing Precautionary Regulation: Do Precaution,Science, and Innovation Go Together?

In this article we argue that the precautionary principle, as applied to the regulation of science and technology, cannot be considered in any general manner inconsistent with the norms and methods of scientific knowledge generation and justification. Moreover, it does not necessarily curtail scientific‐technological innovation. Our argument flows from a differentiated view of what precaution in regulation means. We first characterize several of the most relevant interpretations given to the precautionary principle in academic debate and regulatory practice. We then use examples of actual precaution‐based regulation to show that, even though science can have varying functions in different circumstances and frames, all of those interpretations recur to scientific method and knowledge, and tend to imply innovation in methods, products, and processes. In fact, the interplay of regulation and innovation in precautionary policy, at least in the case of the interpretations of precaution that our analysis takes into account, could be understood as a way of reconciling the two fundamental science and technology policy functions of promotion and control.     

(Re) Defining Emerging Risks

The concept of emergence in risk management can be seen as a revealing symptom of the increasing need for organizations to update their portfolio of risks and opportunities in a rapidly changing and highly competitive environment. Accordingly, the concept of emerging risks has been widely discussed in both scientific and business communities, with, however, a lack of agreement as to whether we should distinguish these risks from others and, if so, what should be the adopted approach for their governance. After reviewing a large set of definitions and conceptions of emerging risks, this article aims at exploring the existence of distinctive features allowing the characterization of a risk as emerging or not. First, we will demonstrate that the features used in the various definitions are ineffective to achieve this distinction. Furthermore, we will argue that all events and consequences associated with risks are or have been states of nature that emerged from complex interactions involving combinations of hazardous activities and stakes. Accordingly, emerging risks are no longer a specific category of risks; they are rather an early step in every risk life cycle that deserves specific governance approaches.     

When Precaution Creates Misunderstandings: The Unintended Effects of Precautionary Information on Perceived Risks,the EMF Case

In the past decade, growing public concern about novel technologies with uncertain potential long‐term impacts on the environment and human health has moved risk policies toward a more precautionary approach. Focusing on mobile telephony, the effects of precautionary information on risk perception were analyzed. A pooled multinational experimental study based on a 5 × 2 × 2 factorial design was conducted in nine countries. The first factor refers to whether or not information on different types of precautionary measures was present, the second factor to the framing of the precautionary information, and the third factor to the order in which cell phones and base stations were rated by the study participants. The data analysis on the country level indicates different effects. The main hypothesis that informing about precautionary measures results in increased risk perceptions found only partial support in the data. The effects are weaker, both in terms of the effect size and the frequency of significant effects, across the various precautionary information formats used in the experiment. Nevertheless, our findings do not support the assumption that informing people about implemented precautionary measures will decrease public concerns.     

Using Structured Decision Making to Help Implement a Precautionary Approach to Endangered Species Management

Endangered species protection is a significant risk management concern throughout North America. An extensive conceptual literature emphasizes the role to be played by precautionary approaches. Risk managers, typically working in concert with concerned stakeholders, frequently cite the concept as key to their efforts to prevent extinctions. Little has been done, however, to evaluate the multidimensional impacts of precautionary frameworks or to assist in the examination of competing precautionary risk management options as part of an applied risk management decision framework. In this article we describe how decision-aiding techniques can assist in the creation and analysis of alternative precautionary strategies, using the example of a multistakeholder committee charged with protection of endangered Cultus Lake salmon on the Canadian west coast. Although managers were required to adopt a precautionary approach, little attention had been given to how quantitative analyses could be used to help define the concept or to how a precautionary approach might be implemented in the face of difficult economic, social, and biological tradeoffs. We briefly review key steps in a structured decision-making (SDM) process and discuss how this approach was implemented to help bound the management problem, define objectives and performance measures, develop management alternatives, and evaluate their consequences. We highlight the role of strategy tables, employed to help participants identify, alternative management options. We close by noting areas of agreement and disagreement among participants and discuss the implications of decision-focused processes for other precautionary resource management efforts.     

The Event: An Underexamined Risk Concept

Some of the terms used in risk assessment and management are poorly and even contradictorily defined. One such term is “event,” which arguably describes the most basic of all risk‐related concepts. The author cites two contemporary textbook interpretations of “event” that he contends are incorrect and misleading. He then examines the concept of an event in A. N. Kolmogorov's probability axioms and in several more‐current textbooks. Those concepts are found to be too narrow for risk assessments and inconsistent with the actual usage of “event” by risk analysts. The author goes on to define and advocate linguistic definitions of events (as opposed to mathematical definitions)—definitions constructed from natural language. He argues that they should be recognized for what they are: the de facto primary method of defining events.