Rational Choices

...It relies on data that have been gathered through either statistical evidence or laboratory experiment...

...By calculating the percentage of the earth's surface that American metropolises occupy, and then estimating the number of collisions with large meteorites in the past, he arrives at a probability of one in 10 million—nothing to worry about but, like a nuclear accident, something that over enough time will occur...

...The analytic approach is used to assess events of low probability, like earthquakes, or events whose probability is so small that so far they have not happened, like a climatic change brought on by industrial pollution...

...Lewis' primary aim is to describe the nature of the dangers we face from modern technology...

...But, as Lewis shows, the empirical approach is not as certain as we might like...

...Current disposal plans, which call for burying the stuff in caves in Nevada, present almost no risk, Lewis says, now or in the future...

...In general, however, his book has a soothing effect on the nerves, teaching one to cast a skeptical eye at most of the health scares that drift to the front of the newspapers these days...

...Reviewed by Barry Gewen New York "Times Book Review," preview editor Occasionally a volume on some controversial issue comes along that is so balanced, so sensible, so down-toearth, it clears away all the fogs and miasmas surrounding the question and leaves people a little smarter than they were before...

...To those who fear being bombarded with radiation from their electrical appliances and other generally benign sources, he points out that in certain contexts radiation has its positive aspects: Because the radioactive isotope C" is found in grapes, real wine registers on geiger counters, whereas fraudulent beverages synthesized from nonradioactive materials like petroleum do not...

...Only the first part of Lewis' book, entitled "Generalities," deals with the techniques of risk assessment...

...Risk is inherent in the gadgets we depend on, indeed in life itself...

...One, the empirical approach, is what most of us mean by scientific method...

...Although the majority of analytic models are vastly more complicated, the most catastrophic risks—the ones that cause people the greatest concern—are calculated in this way...

...Discussing the 55 mile per hour speed limit, for example, he calculates that the cost of each life saved (based on the value of time lost) amounts to approximately $5 million, "substantially more than is spent in most other regulatory activities...

...As in the initial section, Lewis is never less than enlightening and engaging...

...If we weren't killing ourselves at the rate of 46,000 a year through automobile accidents, wewouldbe committing slaughter on horseback—probably, says Lewis, at higher rates for comparable distances...

...The years he has spent explaining arcane matters to technophobic laymen apparently have taught him how to communicate to a wide audience...

...But for the time being, it is unquestionably the most persuasive...

...city some time in the next 10 years...

...Perfect safety is impossible...

...Nevertheless, the abstract constructs are useful (a good thing, because we depend on them to determine the likelihood of meltdowns at nuclear power plants...

...Since we can never eliminate technological threats—a commercial nuclear accident is inevitable, given enough time—the best we can do is minimize them by making rational choices...

...Overpopulation seems to be his favorite cause among the Big Issues...

...Similarly, those who fret over the cancer-causing pesticides they are ingesting at their dinner tables have more to worry about from the natural carcinogens found in mushrooms, peanuts and dried basil...

...His first lesson, though, is that there is no free lunch...

...Thus, we have had enough empirical experience with lung cancer to know that Quitting Smoking Now Greatly Reduces Serious Risks to Your Health...

...Through these, the highly dramatic recent technological disasters at Bhopal, Chernobyl and Three Mile Island are examined, along with subjects that have become the focus of wide, often ill-informed debate—saccharin, radon, asbestos, nuclear winter...

...Lewis, an expert on risk assessment, is a prof essor of physics at the University of California, Santa Barbara, but he doesn't write like one...

...Even if we were living ontopofthe caves, the radon in our li ving rooms would pose a greater threat than leakage from below...

...even the most mathematically terrified among us should be able to grasp his explanation of the standard deviation...

...Lewis is so skillful, so charming a writer that one may find oneself being seduced by his style alone—his conclusions, after all, can be evaluated only by other experts...

...Not that he is without worries of his own...

...How, Lewis asks, can we arrive at a determination about a particular substance without doing tests on a million mice...

...It is certainly possible that his will not be the last word on the subject...

...His book is free of jargon, of calculus, of complicated graphs, and his few necessary forays into statistical theory are lucid and nonthreatening...

...To demonstrate the analytic approach, Lewis considers the probability of alarge meteorite falling on a major U.S...

...He outlines two avenues for constructively assessing risk, and writes entertainingly about each...

...The Department of Health and Human Services attempts to identify chemicals that have a one in a million chance of causing cancer during an individual's lifetime...

...The dangers of lead poisoning trouble him, and if you were to light up a cigarette in his company you might get a stern lecture, complete with horrifying statistics...

...Alarmism in any form gets Lewis' goat, and no alarmists annoy him more than the protesters who claim nuclear waste is a reason to prohibit nuclear energy...

...Lewis' TechnologicalRiskis suchawork.lt should beread by anyone concerned about toxic chemicals, the Greenhouse Effect, nuclear waste, and other similarly evil accompaniments of present-day civilization...

...Nuclear waste disposal, he insists, "is a phoney issue, and it would be in the national interest to get on to more important matters...

...Since the conditions for these risks cannot be tested in a laboratory, the assessors have to depend on theoretical models for results, while recognizing that the models cannot take every possible contingency into account...

...Another of his aims in this book is to show how difficult risk assessment can be...

...The second part, "Specifics," takes up individual issues—toxic chemicals, automobile and airline safety, radiation, etc...

...The experimenters' solution, he explains, is to breed rodents that are especially susceptible to the chemical in question, expose them to massive doses, and then make "vast extrapolations...

...Whatever its hazards, he continually reminds us, technology has extended life and dramatically increased its comforts...

...If empirical techniques are less than entirely satisfactory, the second avenue Lewis discusses often amounts to little more than educated guesswork...