For years, Americans have been concerned about outdoor air pollution. So concerned that, in 1990, Congress passed a thousand-page amendment to the Clean Air Act to clean up the outdoor air-which will cost taxpayers about $25 billion a year. Scientific evidence, however, suggests that indoor air pollution poses a greater risk to people's health than outdoor air, says John Graham, professor of policy and decision sciences at the School of Public Health and director of the Harvard Center for Risk Analysis (HCRA). Yet, he adds, there's no particular public demand for addressing indoor air quality. "We live in a society that is both paranoid and neglectful about dangers at the same time," he says.
Graham and his colleagues at HCRA are trying to promote a reasoned public response to health, safety, and environmental hazards by encouraging rigorous application of science-based risk assessment, risk-ranking methods, and cost-benefit analysis. They routinely testify on regulatory reform before committees in the U.S. House and Senate, they write articles for scientific journals, and they publish Risk in Perspective, a newsletter mailed to 14,000 opinion leaders, journalists, members of Congress, business executives, and environmental advocates.
In 1994, Graham appeared on an ABC-TV program that discussed various fears gripping America: fear of the food we eat, the water we drink, the air we breathe. Fear of airplanes, power lines, cellular phones. "There are real risks to worry about," said ABC reporter John Stossel, "but, for the most part, we're worrying about the wrong ones." He pointed out that when seven people died after ingesting tainted Tylenol, Americans spent more than $1 billion sealing products in tamper-resistant packages. Yet, he said, 50 children are killed every year by ordinary five-gallon buckets. They fall into them and drown, but that doesn't make news because buckets aren't new. "The mysterious, the bizarre, the speculative make good news," Graham told Stossel. But common fatalities don't get attention because the media don't have a hook to sell them.
Graham recently conducted a random survey of 1,000 Americans to identify public perceptions of health hazards. Not surprisingly, the results suggest that the greater the number of national news stories about a hazard, the more likely the public is to believe that it is real (see the quiz, next page). The most interesting finding, however, is a large gender gap, says Graham. Even after controlling for such variables as educational background and values, women are much more likely than men to believe that something is dangerous. For example, 68 percent of the women surveyed-but only 50 percent of the men-considered pesticide residues on fruits and vegetables a health risk.
Graham and his colleagues are now comparing results from their first survey with a similar poll of scientific experts. A disturbing finding, Graham says, is that lay people tend to evaluate ionizing radiation-from radon in their homes or from medical x-rays-as almost the same as nonionizing radiation, like electric and magnetic fields from power lines or cellular phones. (The scientific evidence for danger from ionizing radiation is much stronger.) Such discoveries have implications for how reporters need to interpret health information for ordinary citizens.
James Hammitt '78, M.P.P. '81, Ph.D. '88, associate professor of health policy and management, chides journalists for failing to give the public a sense of the relative probability of harm. "People think that rare events are much more common than they are," he says. A catastrophe like this spring's ValuJet crash, for instance, garners more press attention than car accidents, even though people are much more likely to be killed or injured on highways than in airline travel. (For a 1,000-mile trip, flying on a commercially scheduled jet airliner is about 10 times safer, in terms of fatalities, than driving a car.)
Government agencies like the FDA also mislead the public, says Graham. "There've been studies of large populations of women who have had breast implants for years, comparing them with women who have not," he says. "We've looked at the symptoms reported, and they aren't any more frequent among women with breast implants. But it's very difficult for the government to turn around and say, 'Oops, we were wrong. Breast implants aren't hazardous.' Don't hold your breath until that happens."
Graham says there is evidence that if people are unfamiliar with a technology, they will be more concerned about its dangers. For example, lay people may not understand a nuclear power plant, and that will increase their level of concern. But they think they understand an automobile, so even though it's potentially dangerous, they're not so worried about it. "If people react too much on that principle, they can suffer from this syndrome of being paranoid and neglectful," Graham says. "If we focus our resources on what's scary, rather than on what kills people, in the process we may end up committing a form of statistical murder."
