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sample of individuals from an entire population. But other experts criticized the Lancet authors for using too few. “I wouldn’t survey a junior high school, no less an entire country, using only 47 cluster points,” said Steven Moore, a Republican consultant who had conducted polling in Iraq for Coalition forces. One of the Lancet authors, Gilbert Burnham, replied that “surveying more clusters would have also meant more risk to the survey team.” He said, “Had we used 470 clusters, our range of plausible values would have been about 3 times narrower.” It is also possible that the results would have been far different.

Indeed, a survey of Iraq by the United Nations Development Programme used 2,200 cluster points, compared to only 33 used by the first Lancet study conducted four months later. And the study—Iraq Living Conditions Survey 2004—estimated only 24,000 deaths, roughly one quarter as many as The Lancet estimated at the time.

CONVERGENCE

In Chapter 6 we mentioned the notion of convergent evidence, and said that when different methods arrive at similar estimates, those estimates are more credible. The reverse is also true: when results diverge, we should be more cautious. To be sure, the Lancet studies seem to support each other, but both produced results that are far higher than those of others. The Iraq Body Count project, for example, tabulated in November 2006 that between 47,016 and 52,142 deaths had been reported in Iraqi and international news media as a result of the 2003 invasion and the continuing violence. That’s just 7 to 8 percent of The Lancet’s 654,965 figure published the previous month. It’s true that the IBC estimates almost certainly missed some deaths that weren’t reported, but we judge it unlikely that they could miss so many.

The 2004 Lancet study was inconsistent both with the Iraq Body Count tabulations and with the United Nations survey. Shortly after The Lancet had estimated 98,000 war deaths, the Iraq Body Count put the count between 14,619 and 16,804 as of December 7, 2004. The United Nations survey estimates war deaths at between 18,000 and 29,000, with the midpoint of that range at 24,000.

After the second Lancet study, Iraq Body Count officials issued a “reality check,” disputing it and pointing out inconsistencies with other data. Delving into the details, they said that if the Lancet study was valid it would mean, among other improbabilities, that an average of 1,000 Iraqis had been killed by violence every single day in the first half of 2006, but that only one of those killings in ten had been noticed by any public surveillance mechanism. They said it also would mean 800,000 Iraqis suffered blast wounds or other serious conflict-related injuries over the preceding two years and that 90 percent of them went unnoticed by hospitals.

We can’t say the Lancet studies are wrong. Unlike Mitch Snyder’s “meaningless” estimate of 3 million homeless persons, which we discussed in Chapter 6, the Lancet estimates both were derived using scientifically accepted methods and were published in a reputable, peer-reviewed journal. The findings also are stoutly defended not only by the authors but by some independent experts as well. Nevertheless, given both the extraordinary imprecision of the figures and their failure to square with other observations, we can’t accept them as accurate until and unless validated by other researchers using a much larger sample.

FINAL RULE: Be Skeptical, but Not Cynical

THE SKEPTIC DEMANDS EVIDENCE, AND RIGHTLY SO. THE CYNIC ASSUMES that what he or she is being told is false. Throughout this book we’ve been urging you to be skeptical of factual claims, to demand and weigh the evidence and to keep your mind open. But too many people mistake cynicism for skepticism. Cynicism is a form of gullibility—the cynic rejects facts without evidence, just as the naïve person accepts facts without evidence. And deception born of cynicism can be just as costly or potentially as dangerous to health and well-being as any other form of deception.

To understand this notion, consider