How Bad Is It in Iraq?
Wednesday, January 16, 2008
A study based on the Iraq Family Health Survey (IFHS) and recently
published in the New England Journal of Medicine sheds new light
on violent deaths in Iraq. It estimates that violent deaths are
2-4 times higher than the tally of civilian deaths collected from
media reports by Iraq Body Count (IBC). This disparity is unsurprising,
since that tally attempts to screen out combatant deaths, and
media reports will miss some deaths. The study period ended in
June of 2006: applying the same ratio to the current IBC tally
would give a death toll in the 150,000-300,000 range.
This fits with the earlier ILCS survey, which estimated violent
deaths 2-3 times the contemporary IBC count. This
estimate based on cemetery traffic suggests a ratio in the
2.5-4.5 times range.
The study by Burnham et al published in The Lancet estimated
violent deaths 10-20 times higher than IBC. There’s an obvious
conflict between Burnham et al and IFHS. IFHS had a larger sample
size, more resources and better supervision. Both studies failed
to survey some of the planned clusters: 11% in IFHS, 6% in Burnham
et al. IFHS made an effort to compensate for the missed clusters,
Burnham et al did not. IFHS also made an effort to reflect regional
population changes from migration during the study period. Burnham
et al did not.
Some supporters of Burnham et al are still defending that study.
One argument they make is that IFHS isn’t so different if
you measure “excess death,” that is the increase in
death rates, including nonviolent deaths, over pre-war conditions.
I don’t think this works: the IFHS authors didn’t
try to calculate that and argued, I think correctly, that recall
was worse for the pre-war period. Certainly the recalled death
rate for that period was low compared to neighboring countries.
Subtracting the pre-invasion death-rate from the post invasion
rate could give a spurious increase because of recall issues.
Supporters of Burham et al also complain that the IFHS annual
death rate does not show the strong increase from 2003 to 2006
recorded in other sources. However, the range of sampling error
is substantial for the annual figures, and the difference in the
IFHS trendline and that shown by IBC is not statistically significant.
One of the strengths of the IFHS data is that it also looked
at other demographic data, and the large sample size narrowed
the margin of error. If Burnham et al was closer to the truth
about violent deaths than IFHS, the result should be visible in
the IFHS demographic data. If 2.5% of the population is being
killed in an armed conflict, (as Burnham et al claim) and most
of those deaths are military-age males (one of the few points
on which Burnham et al and IBC agree), then the result should
be a strong male/female imbalance in adult Iraqi demographics.
The predicted imbalance does not occur in the IFHS data, except
for the cohort that was unfortunate enough to reach fighting age
back when Saddam Hussein was invading his neighbors.