Hazards of modern life tend to be assessed differently by specialists and non-specialists. It is not so much a conflict of answers, but of questions asked in the first place.
Which is more dangerous for UK residents, atomic energy or stepladders?
Is this more dangerous...
On the one hand, "nuclear power has not killed anybody in the UK and very few people elsewhere," says no less an authority than Ian Fells, Professor Emeritus of Energy Conversion at the University of Newcastle, and currently Chairman of the Centre of Excellence for New and Renewable Energy.
On the other hand, the government's Department of Trade and Industry reports that "one person a week is killed in accidents involving ladders." So, in the interest of public safety, this comparison proves we should green light nuclear stations and put a stop to do it yourself, right?
Not quite, but it highlights the problem of assessing technologies by the numbers alone.
Quantitative - approach of the experts
...than that?
Although risk assessment surely dates back to prehistory (e.g. a caveman deciding how closely to stalk his prey, such that he kills it rather than vice versa), 'doing the numbers' of technology risk is a relatively young science. It started in the 1950s with engineering studies aimed at finding a safe design for nuclear reactors. By 1975 this had evolved to 'probabilistic risk assessment', which has since grown into an industry employing tens of thousands of engineers, scientists and regulators.
Probabilistic risk assessment, or PRA, is an expert's game. It depends heavily on analytical, mathematical and computing tools that are inaccessible to lay people: Monte Carlo analyses, influence diagrams, multiple attributes, minimum cut sets, fault trees and the like. The science is fast-moving as well as voluminous. For instance, since 1986 the US Environmental Protection Agency (EPA) has published 5,000 pages of guidance on how PRA should be done.
The core of PRA, when applied to an object as complex as a space shuttle or as mundane as a new detergent, is the so-called 'triplet of risk':
1.What can go wrong?
2.How likely is that to happen?
3.What are the consequences if it does happen?
Although PRA itself is complex, its outputs are simple. Consequences, at a human level, typically are expressed as mortality. In other words, X people will die if, for instance, the bridge collapses, the plane crashes or the chemicals are released.
Economists can translate this into something even more understandable, money. According to researchers at the Free University of Amsterdam, the European Union in its policy studies currently values a single human life at an average of one million euros (USD 833,000) - generally referred to as the 'one-million-euro rule'. So, the annual public cost of stepladder usage in the UK is at least €52 million euros, while that of nuclear power is €0, right?
Not quite, but the comparison highlights the importance of non-quantitative factors in risk assessment.
Not just whether you die, but how
As PRA blossomed in the late 1970s and early 1980s, complicated, complex technologies became ever clearer and more manageable - to the experts, that is. To the general public, ironically, they actually became more obscure and frightening. A primary object of contention was (and still is) nuclear power: according to PRA it is relatively low risk compared to, say, driving a car, and its dangers have diminished over the years as technical know-how has increased. Of course this is at odds with perceptions of lay people, who over the years have become more fearful about it, not less.
This is simply irrational or ignorant, according to some experts. The problem, they say, is a lack of communication plus an inability to understand basic maths. The solution, they add, is more science. Legal scholar Stephen Breyer (now a Supreme Court Justice) went so far as to advocate creation of a US federal agency charged with creating uniformity and rationality in technology risk assessment. The agency was proposed (albeit not adopted) to the Senate as part of the Comprehensive Regulatory Reform Act of 1995.
The need for something to worry about
Some critics also see public fears of technology as a reflex of an over-pampered society. Now that most Europeans and Americans need not worry about food, clothes and shelter, they have invented worries about hazards in them. They are biting the hand that feeds them - a luxury that earlier, harder-working generations could not afford.
Meanwhile, over the past quarter-century another explanation has developed that considers public concerns to be neither foolish nor uninformed. University of Oregon Professor Paul Slovic pioneered the idea that when judging risk, ordinary people add to mortality two additional fear factors: dread and unknown. The most dreaded technologies are potentially catastrophic, dangerous to future generations, involuntary and uncontrollable. Unknown ones are where the dangers are hidden, delayed in time or simply not yet recognisable.
Nuclear power is, once again, the classic example. Whatever its safety record, the public consistently ranks it highly on dread and unknown. As Karen Bickerstaff of the University of East Anglia's Centre for Environmental Risk points out, lay people see atomic energy as far more dangerous than bicycles or power tools, even though experts judge the latter to be more likely causes of individual harm.
Slovic: ‚risk is subjective‘
Finally, there is the key issue of trust. Ordinary people are more willing to punt on a new technology, say Slovic, Bickerstaff and other researchers, if they believe they can rely on the authorities to protect their lives and livelihoods. If the authorities are seen to be incompetent or uninterested, if the people feel treated as pawns or guinea pigs, most will dig in their heels and oppose potentially harmful technologies.
The leading cause of death? Life
So while the PRA crowd sees risk as objective, the Slovic camp sees it as subjective. As Slovic himself argues: "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 chemical's carcinogenic risk are both based on theoretical models, whose structure is subjective and assumption-laden, and whose inputs are dependent on judgment….Non-scientists have their own models, assumptions, and subjective assessment techniques (intuitive risk assessments), which are sometimes very different from the scientists' models."
Not at all does Slovic reject PRA: instead he maintains that it should be blended with the acceptance that public concerns are both real and legitimate. The US EPA already has done this to some extent. The bulk of its budget in recent years has been aimed at hazardous waste, primarily because the public sees it as America's most serious environmental threat, even though experts say indoor air pollution is a greater health risk.
Clearly, this has implications for other policies, among others chemicals, genetically modified organisms, nanotechnology, nuclear power and yes, even stepladders. (Check out The Stepladder Users' Guide at www.dti.gov.uk/homesafetynetwork/dy_stepladder.htm.)
So, if we address the risk concerns of both experts and lay people in an atmosphere of trust, nuclear power can become as non-controversial as stepladders, right?
Not quite, but at least both groups might be talking to each other rather than past each other.
