- President Bush's off-hand summation last month of the
number of Iraqis who have so far died as a result of our invasion and occupation
as "30,000, more or less" was quite certainly an under-estimate.
The true number is probably hitting around 180,000 by now, with a possibility,
as we shall see, that it has reached as high as half a million.
-
- But even Bush's number was too much for his handlers
to allow. Almost as soon as he finished speaking, they hastened to downplay
the presidential figure as "unofficial", plucked by the commander
in chief from "public estimates". Such calculations have been
discouraged ever since the oafish General Tommy Franks infamously announced
at the time of the invasion: "We don't do body counts". In December
2004, an effort by the Iraqi Ministry of Health to quantify ongoing mortality
on the basis of emergency room admissions was halted by direct order of
the occupying power.
-
- In fact, the President may have been subconsciously
quoting figures published by iraqbodycount.org, a British group that diligently
tabulates published press reports of combat-related killings in Iraq. Due
to IBC's policy of posting minimum and maximum figures, currently standing
at 27787 and 31317, their numbers carry a misleading air of scientific
precision. As the group itself readily concedes, the estimate must be incomplete,
since it omits unreported deaths.
-
- There is however another and more reliable method for
estimating figures such as these: nationwide random sampling. No one doubts
that, if the sample is truly random, and the consequent data correctly
calculated, the sampled results reflect the national figures within the
states accuracy. That, after all, is how market researchers assess public
opinion on everything from politicians to breakfast cereals. Epidemiologists
use it to chart the impact of epidemics. In 2000 an epidemiological team
led by Les Roberts of Johns Hopkins School of Public Health used random
sampling to calculate the death toll from combat and consequent disease
and starvation in the ongoing Congolese civil war at 1.7 million. This
figure prompted shocked headlines and immediate action by the UN Security
Council. No one questioned the methodology.
-
- In September 2004, Roberts led a similar team that researched
death rates, using the same techniques, in Iraq before and after the 2003
invasion. Making "conservative assumptions" they concluded that
"about 100,000 excess deaths" (in fact 98,000) among men, women,
and children had occurred in just under eighteen months. Violent deaths
alone had soared twentyfold. But, as in most wars, the bulk of the carnage
was due to the indirect effects of the invasion, notably the breakdown
of the Iraqi health system. Thus, though many commentators contrasted the
iarqbodycount and Johns Hopkins figures, they are not comparable. The bodycounters
were simply recording, or at least attempting to record, deaths from combat
violence, while the medical specialists were attempting something far more
complete, an accounting of the full death toll wrought by the devastation
of the US invasion and occupation.
-
- Unlike the respectful applause granted the Congolese
study, this one, published in the prestigious British medical journal The
Lancet, generated a hail of abusive criticism. The general outrage may
have been prompted by the unsettling possibility that Iraq's liberators
had already killed a third as many Iraqis as the reported 300,000 murdered
by Saddam Hussein in his decades of tyranny. Some of the attacks were self-evidently
absurd. British Prime Minister Tony Blair's spokesman, for example, queried
the survey because it "appeared to be based on an extrapolation technique
rather than a detailed body count", as if Blair had never made a political
decision based on a poll. Others chose to compare apples with oranges by
mixing up nationwide Saddam-era government statistics with individual cluster
survey results in order to cast doubt on the latter.
-
- Some questioned whether the sample was distorted by
unrepresentative hot spots such as Fallujah. In fact, the amazingly dedicated
and courageous Iraqi doctors who actually gathered the data visited 33
"clusters" selected on an entirely random basis across the length
and breadth of Iraq. In each of these clusters the teams conducted interviews
in 30 households, again selected by rigorously random means. As it happened,
Fallujah was one of the clusters thrown up by this process. Strictly speaking,
the team should have included the data from that embattled city in their
final result - random is random after all -- which would have given an
overall post-invasion excess death figure of no less than 268,000. Nevertheless,
erring on the side of caution, they eliminated Fallujah from their sample.
-
- For such dedication to scholarly integrity, Roberts
and his colleagues had to endure the flatulent ignorance of Michael E.
O'Hanlon, sage of the Brookings Institute, who told the New York Times
that the self-evidently deficient Iraqbodycount estimate was "certainly
a more serious work than the Lancet report".
-
- No point in the study attracted more confident assaults
by ersatz statisticians than the study's passing mention of a 95 per cent
"confidence interval" for the overall death toll of between 194,000
and 8,000. This did not mean, as asserted by commentators who ought to
have known better, that the true figure lay anywhere between those numbers
and that the 98,000 number was produced merely by splitting the difference.
In fact, the 98,000 figure represents the best estimate drawn from the
data. The high and low numbers represented the spread, known to statisticians
as "the confidence interval", within which it is 95 per cent
certain the true number will be found. Had the published study (which was
intensively peer reviewed) cited the 80 per cent confidence interval also
calculated by the team - a statistically respectable option -- then the
spread would have been between 152,000 and 44,000.
-
- Seeking further elucidation on the mathematical tools
available to reveal the hidden miseries of today's Iraq, I turned to CounterPunch's
consultant statistician, Pierre Sprey. He reviewed not only the Iraq study
as published in the Lancet, but also the raw data collected in the household
survey and kindly forwarded me by Dr. Roberts.
-
- "I have the highest respect for the rigor of the
sampling method used and the meticulous and courageous collection of the
data. I'm certainly not criticizing in any way Robert's data or the importance
of the results. But they could have saved themselves a lot of trouble had
they discarded the straitjacket of Gaussian distribution in favor of a
more practical statistical approach", says Sprey. "As with all
such studies, the key question is that of 'scatter' i.e. the random spread
in data between each cluster sampled. So cluster A might have a ratio of
twice as many deaths after the invasion as before, while cluster B might
experience only two thirds as many. The academically conventional approach
is to assume that scatter follows the bell shaped curve, otherwise known
as 'normal distribution,' popularized by Carl Gauss in the early 19th century.
This is a formula dictating that the most frequent occurrence of data will
be close to the mean, or center, and that frequency of occurrence will
fall off smoothly and symmetrically as data scatters further and further
from the mean - following the curve of a bell shaped mountain as you move
from the center of the data.
-
- "Generations of statisticians have had it beaten
in to their skulls that any data that scatters does so according to the
iron dictates of the bell shaped curve. The truth is that in no case has
a sizable body of naturally occurring data ever been proven to follow the
curve". (A $200,000 prize offered in the 1920s for anyone who could
provide rigorous evidence of a natural occurrence of the curve remains
unclaimed.)
-
- "Slavish adherence to this formula obscures information
of great value. The true shape of the data scatter almost invariably contains
insights of great physical or, in this case medical importance. In particular
it very frequently grossly exaggerates the true scatter of the data. Why?
Simply because the mathematics of making the data fit the bell curve inexorably
leads one to placing huge emphasis on isolated extreme 'outliers' of the
data.
-
- "For example if the average cluster had ten deaths
and most clusters had 8 to 12 deaths, but some had 0 or 20, the Gaussian
math would force you to weight the importance of those rare points like
0 or 20 (i.e. 'outliers') by the square of their distance from the center,
or average. So a point at 20 would have a weight of 100 (20 minus 10 squared)
while a point of 11 would have a weight of 1 (11 minus 10 squared.)
-
- "This approach has inherently pernicious effects.
Suppose for example one is studying survival rates of plant- destroying
spider mites, and the sampled population happens to be a mix of a strain
of very hardy mites and another strain that is quite vulnerable to pesticides.
Fanatical Gaussians will immediately clamp the bell shaped curve onto the
overall population of mites being studied, thereby wiping out any evidence
that this group is in fact a mixture of two strains.
-
- "The commonsensical amateur meanwhile would look
at the scatter of the data and see very quickly that instead of a single
"peak" in surviving mites, which would be the result if the data
were processed by traditional Gaussian rules, there are instead two obvious
peaks. He would promptly discern that he has two different strains mixed
together on his plants, a conclusion of overwhelming importance for pesticide
application".
-
- (Sprey once conducted such a statistical study at Cornell
- a bad day for mites.)
-
- So how to escape the Gaussian distortion?
-
- "The answer lies in quite simple statistical techniques
called 'distribution free' or 'non parametric' methods. These make the
obviously more reasonable assumption that one hasn't the foggiest notion
of what the distribution of the data should be, especially when considering
data one hasn't seen -- before one is prepared to let the data define its
own distribution, whatever that unusual shape may be, rather than forcing
it into the bell curve. The relatively simple computational methods used
in this approach basically treat each point as if it has the same weight
as any other, with the happy result that outliers don't greatly exaggerate
the scatter.
-
- "So, applying that simple notion to the death rates
before and after the US invasion of Iraq, we find that the confidence intervals
around the estimated 100,000 "excess deaths" not only shrink
considerably but also that the numbers move significantly higher. With
a distribution-free approach, a 95 per cent confidence interval thereby
becomes 53,000 to 279,000. (Recall that the Gaussian approach gave a 95
per cent confidence interval of 8,000 to 194,000.) With an 80 per cent
confidence interval, the lower bound is 78,000 and the upper bound is 229,000.
This shift to higher excess deaths occurs because the real, as opposed
to the Gaussian, distribution of the data is heavily skewed to the high
side of the distribution center".
-
- Sprey's results make it clear that the most cautious
estimate possible for the Iraqi excess deaths caused by the US invasion
is far higher than the 8,000 figure imposed on the Johns Hopkins team by
the fascist bell curve. (The eugenicists of the 1920s were much enamored
of Gaussian methodology.) The upper bounds indicate a reasonable possibility
of much higher excess deaths than the 194,000 excess deaths (95 per cent
confidence) offered in the study published in the Lancet.
-
- Of course the survey on which all these figures are based
was conducted fifteen months ago. Assuming the rate of death has proceeded
at the same pace since the study was carried out, Sprey calculates that
deaths inflicted to date as a direct result of the Anglo-American invasion
and occupation of Iraq could be, at best estimate, 183,000, with an upper
95 per cent confidence boundary of 511,000.
-
- Given the generally smug and heartless reaction accorded
the initial Lancet study, no such updated figure is likely to resonate
in public discourse, especially when it registers a dramatic increase.
Though the figures quoted by Bush were without a shadow of a doubt a gross
underestimate (he couldn't even be bothered to get the number of dead American
troops right) 30,000 dead among the people we were allegedly coming to
save is still an appalling notion. The possibility that we have actually
helped kill as many as half a million people suggests a war crime of truly
twentieth century proportions.
-
- In some countries, denying the fact of mass murder is
considered a felony offence, incurring harsh penalties. But then, it all
depends on who is being murdered, and by whom.
-
- Andrew Cockburn is the co-author, with Patrick Cockburn,
of Out of the Ashes: the Resurrection of Saddam Hussein.
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