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Valuing the Protection of Ecological Systems and Services: Lessons from the Risk Assessment Battlefield. Paul Slovic Decision Research 1201 Oak Street Eugene, Oregon, USA pslovic@darkwing.uoregon.edu June 14, 2004. France.
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Valuing the Protection of Ecological Systems and Services: Lessons from the Risk Assessment Battlefield Paul Slovic Decision Research 1201 Oak Street Eugene, Oregon, USA pslovic@darkwing.uoregon.edu June 14, 2004
Polarized views, controversy and overt conflict have become pervasive within risk assessment and risk management. Frustrated scientists and industrialists castigate the public for behaviors they judge to be based on irrationality or ignorance. Members of the the public feel similarly antagonistic toward industry and government. • This dissatisfaction can be traced, in part, to a failure to appreciate the complex and socially determined nature of the concept “risk.”
Risk as Analysis • Risk as Feelings • Risk as Politics
Risk Assessment Identification Quantification Characterization Risk Management Decision making Acceptable risk How safe is safe enough? Communication Evaluation Risk Analysis • Politics Risk perception Values Process issues: Who decides? Power Trust Conflict/Controversy
What Is Risk? • Risks as hazards • “Which risks should we rank?” • Risk as probability • “What is the risk of getting AIDS from an infected needle? • Risk as consequence • “What is the risk of letting your parking meter expire?” Answer: “Getting a ticket.” • Risk as potential adversity • “How great is the risk of riding a motorcycle?” • Here, risk is some unspecified blend of probability and payoff. The language of risk is problematic!
What Is Risk? • Risk does not exist “out there,” independent of our minds and cultures, waiting to be measured. • Human beings have invented the concept risk to help them understand and cope with dangers and uncertainties of life. • There is no such thing as “real risk” or “objective risk.” The nuclear engineer’s probabilistic risk estimate for a nuclear accident or the toxicologist’s quantitative estimate of a carcinogenic risk are both based on theoretical models, whose structure is subjective and assumption-laden, and whose inputs are dependent on judgment.
One way in which subjectivity permeates risk assessment is its dependence on judgments in every stage of the process, from the initial structuring of a risk problem to deciding which endpoints or consequences to include in the analysis, identifying and estimating exposures, choosing dose-response relationships, and so on.
Selecting Endpoints for Analysis • An adequate risk characterization must include all impacts of concern to those at risk and of concern to those responsible for decision making. Selection of endpoints is another act of judgment.
Selecting Endpoints for Analysis • Risk characterization typically focuses on only a few select endpoints such as cancer or birth defects. However, an adequate characterization may also need to include effects on the immune system and related systems (allergenicity), neurological effects, behavioral effects, and effects on reproduction and development. Psychological impacts (e.g., anxiety, depression) and ecological impacts may also be important.
Is coal mining getting safer? It depends on which measure you choose. Accidental deaths per thousand coal mine employees in the United States Choosing a Measure of Risk • Accidental deaths per million tons of coal mined • in the United States
Choosing a Risk Measure • Some ways of expressing mortality risks • Deaths per million people in the population • Deaths per million people within x miles of the source of exposure • Deaths per unit of concentration • Deaths per facility • Deaths per ton of air toxic released • Deaths per ton of air toxic absorbed by people • Deaths per ton of chemical produced • Deaths per million dollars of product produced • Loss of life expectancy associated with exposure to the hazard
Each way of summarizing deaths embodies its own set of values • Counting fatalities gives equal weight to • young and old • painful and nonpainful • voluntary and involuntary • fair (beneficial) and unfair (no benefit) • Loss of life expectancy treats deaths of young people as more important than deaths of older people
Ambiguity in ‘Sound Science’ RISKS OF DIFFERENT ELECTRICITY GENERATING TECHNOLOGIES UNDER ASSUMPTIONS OF 32 OFFICIAL STUDIES (1980-1996) risk as US c/kWh, 1990 base low risk high risk Source: A.C. Stirling
The Multidimensional Nature of Risk • The public has a broad conception of risk, qualitative and complex, that incorporates considerations such as uncertainty, dread, catastrophic potential, controllability, equity, risk to future generations, and so forth, into the risk equation.
Values Underlie Risk • There are legitimate, value-laden issues underlying these multiple dimensions of risk, and these dimensions need to be considered in risk-policy decisions. • For example, is risk from cancer (a dread disease) worse than risk from auto accidents (not dreaded)? Is a risk imposed on a child more serious than a known risk accepted voluntarily by an adult? Are the deaths of 50 passengers in separate automobile accidents equivalent to the deaths of 50 passengers in one airplane crash?
The fact that hazards differ dramatically in their attributes or characteristics helps explain why certain technologies or activities, such as nuclear power, evoke much more serious public opposition than others, such as motorcycle riding, that cause many more fatalities. It is presumptuous for technical experts to act as if they know, without careful thought and analysis, the proper weights to use to equate one type of hazard with another. When lay and expert values differ, reducing different kinds of hazard to a common metric (such as number of fatalities per year) and presenting comparisons only on that metric have great potential to produce misunderstanding and conflict and to engender mistrust of expertise. (“Improving Risk Communication,” National Academy of Sciences, p. 52)
Defining risk is an exercise of power! Whoever controls the definition of risk controls the rational solution to the problem at hand. If you define risk one way, then one option will rise to the top as the most cost-effective or the safest or the best. If you define it another way, perhaps incorporating socially important values, you will likely get a different ordering of your action solutions.
WorldviewsCulture determines salient values • Douglas & Wildavsky (1982): Every cultural group attends to some risk and ignores other to maintain a particular way of life. - Hierarchist (support superior/subordinate social relations and detest civil disobedience - Individualists (support self-regulation, individual achievement and reward and dislike social rules that constrain individual initiative) - Egalitarians (support broad distribution of power and wealth and dislike ranked role differentiation) - Fatalists (see nature as capricious and thus uncontrollable)
Other influences on risk assessments: • gender: the white male effect • affiliation bias • even for scientists
Importance of Trust “Acceptance of any risk is more dependent on public confidence in risk management than on quantitative estimates of risk” C. Starr
Trust: The Asymmetry Principle • It is far easier to destroy trust than to create it! • Negative (trust-destroying) events outweigh positive events • Negative events more sharply defined (accidents, lies) • Positive events often fuzzy or indistinct e.g., how many positive events are represented by the safe operation of a nuclear power plant for one day? • Sources of bad news are more credible than sources of good news • Risk is easier to demonstrate than absence of risk
Restrict public input Florida law Congress vs. Nevada Stephen Breyer’s view Expand public input make risk assessment sensitive to public views Improve mechanisms for public participation Power sharing Negotiation Process is the key — Not more quantitative risk assessment Where Next?
The limitations of risk science, the importance and difficulty of maintaining trust, and the subjective and contextual nature of risk point to the need for a new approach — one that focuses upon introducing more public participation into both risk assessment and risk decision making in order to make the decision process more democratic, improve the relevance and quality of technical analysis, and increase the legitimacy and public acceptance of the resulting decisions.
The Risk Game • The concept of risk is like the concept of a game. Games have time limits, rules of play, opponents, criteria for winning or losing, and so on, but none of these attributes is essential to the concept of a game, nor is any of them characteristic of all games.
The Risk Game • Similarly, a sociopolitical view of risk assumes that risks are characterized by some combination of attributes such as voluntariness, probability, intentionality, equity, and so on, but that no one of these attributes is essential. The bottom line is that, just as there is no universal set of rules for games, there is no universal set of characteristics for describing risk. The characterization must depend on which risk game is being played.
The Risk Game • The rules of the risk game must be socially negotiated within the context of specific decision problems.
Recognizing interested and affected citizens as legitimate partners in the exercise of risk assessment is no short-term panacea for the problems of risk management. But serious attention to participation and process issues may, in the long run, lead to more satisfying and successful ways to manage risk.
