Stanford News

2/10/97

CONTACT: Stanford University News Service (415) 723-2558


Schneider offers three questions to make a citizen-scientist

It's time to empower Americans to become citizen-scientists, Stanford climatologist Stephen Schneider said in Seattle on Tuesday, Feb. 18, during a session on science and democracy at the annual meeting of the American Association for the Advancement of Science.

Americans at the end of the 20th century face a number of difficult decisions that hinge on scientific expertise ­ about safe ways to store nuclear wastes, for example, or how worthwhile it is to scale back on fossil fuel use to prevent global warming. "Every citizen in a democracy is capable of joining in those decisions," Schneider said, "because in the end they are value judgments based on common sense, plus an awareness of the risks and benefits of alternative strategies."

To make an informed value judgment about something as complex as global warming, however, requires a level of technical information, plus sophistication about scientific facts and methods, that most Americans do not have the time and energy to develop for themselves. Schneider called for establishment of a "meta-institution," an agency partly analogous to the now-defunct Office of Technology Assessment, "to do the hard work of evaluating the likelihood of scientific assertions on important topics."

He said that all citizens and their elected representatives need to develop the confidence to ask experts for appropriate information. He has devised a set of three questions that he says every citizen, journalist and policymaker should remember in trying to get the technical information from experts that citizens need to make informed decisions.

When enough people start asking these questions, he says, perhaps the nation will transcend the current "dueling experts" scenario, where congressional hearings or courtroom juries hear two opposing sides deliver politically selected extremes instead of the current scientific consensus on a given technological problem.

Faced with claims and counter-claims from special interests that bend the facts to their own points of view, Schneider said, "many people feel they can't say anything, that they must be ignorant because they can't understand the details. So they just punt. They kick the decision over to others who supposedly 'know better.' What I call the 'one fax-one-vote' system comes into play, whereby special interests shout loud enough to confuse nearly all lay people. That is how special interests manage to gain equal credibility in the public arena for what really is not a very credible position."

How to use experts well

He said that whether a congressional committee meets to decide if a carbon tax would help slow global warming, or a family decides if they should take out a 30-year mortgage on a house, they are likely to consult experts on the greenhouse effect or future interest rates. Here are three questions they should be asking:

c What can happen?

c What are the odds?

c How do you know?

The question "What can happen?" Schneider said, aims to get the experts to agree on a range of possible outcomes. For example, in his own field, the study of climate change, the majority of scientists predict that at the current rate that humans are discharging extra carbon dioxide into the air, the 21st century will see average global temperatures rise between 1 and 5 degrees Celsius.

"However, what can happen has no policy meaning by itself. What's important is how likely is the event ­ that's why the second question is, 'What are the odds?'" Schneider said. "The majority of climate change experts view the odds of at least 1 degree of global warming at something like 9 out of 10. They say there's less than 10 percent chance that warming over the next century will be less than one degree.

"On the other hand, the probability that the Earth will be hit by an asteroid that could wipe out most living things is estimated to be exceedingly low, something like 1 in 10 million per year. If the probability is that low, it will probably remain an un-dealt-with risk," Schneider said.

The question "How do you know?" probes the values and assumptions that underlie estimates. Science is both objective and subjective, Schneider said, based on facts established by experiments, but also on assumptions about what should be tested by the next round of experiments. The science on any complex topic is always evolving: "There are very few things an honest scientist can claim to know for sure," he said. "Except perhaps the classical laws of motion or gravity. When complex systems are involved, it's inevitable that important decisions must be based on the best available, evolving knowledge."

When he and his fellow scientists are consulted as experts, Schneider said, they must hold themselves to high standards and they must be explicit about the difference between facts, assumptions and values in the information they provide.

"These three questions are the ones I ask my doctors," he said, "because once I know their best estimates about probabilities of adverse consequences, I am the expert on how to take risks with my own health."

He told the story of a 40-year-old woman whose doctors found a suspicious spot on her lung in an X-ray. By asking "What can happen?" she found that it could be a tumor, benign or malignant. By asking "What are the odds?" she found that doctors' opinions differed: Some said less than a 10 percent chance that the spot was a malignant tumor, others said the likelihood was nearer to 50 percent.

"This woman was the best example I know of the citizen-scientist," Schneider said. "She asked the people who were in a better position to know about the probabilities, she asked them why, and then made a value judgment for her own life ­ one that weighed the risks and benefits of various treatment alternatives."

The woman chose a painful surgery to have the possible tumor removed; it turned out to be malignant and so her choice stopped the spread of cancer. But as Schneider frequently tells his students, either decision could have been the "right" one: "How do you know how a gamble's going to turn out? A gamble's a gamble. Risk-averse people like to buy insurance, but premiums aren't free."

An agency to sort out scientific disputes

What happens when scientist A says the probability of some important event is 1 in 4, and scientist B says it's one chance in 400? "That's where the scientific community comes in," Schneider says. "You've got to go with the best guesses of the majority of the best-respected experts ­ even recognizing that every once in a while a scientist with a marginal view may turn out to be right."

How can the average citizen sort out the scientific consensus on the many complicated questions that touch on his or her life? "It's a tall order for the citizen who is casual in hearing the debates," Schneider admitted. "That requires the kind of citizen who religiously watches Nova and reads the Tuesday New York Times science section or Scientific American ­ a good science buff with a nose for phonies."

He credited a handful of people with this level of interest ­ science journalists, and a small handful of politicians and their staff specialists. Most, however, are more used to nosing out political phonies: Schneider says members of Congress and other decision-makers are often easily taken in by Ph.D.s whose advice supports a particular political viewpoint.

"Here's where we need a meta-institution. We need somebody in between the decision-makers, the press and the scientists to help ascertain the best-guess position of the majority of knowledgeable experts," Schneider said. He envisions a quick-response agency, independent of both Congress and the president, that would assemble teams of scientists and lay people for open discussion of scientific claims made in the nation's political and economic arenas.

If the meta-institution found a need for an in-depth study, the National Research Council could conduct it, Schneider said. The agency would act in many ways like the Office of Technology Assessment, which was dismantled by Congress two years ago. But it would conduct all of its deliberations in the open, perhaps by closed-circuit TV.

"This would be a somewhat like a science court, not a court that determines guilt or innocence or what to do about the issues, but simply a court that can evaluate the probability of claims," Schneider said. "I would like to take the process of evaluating scientific credibility out of the political arena and into an open institution that has nothing to do with policy choice, but can call anyone's statement, including statements by the president or the speaker of the house, 'scientific nonsense,' if that is warranted by the best available knowledge."

-30-

EDITORS: Schneider's latest book is Laboratory Earth: The Planetary Gamble We Can't Afford to Lose, BasicBooks, 1997.

-By Janet Basu