I just got page proofs for a new paper on excess deaths in Iraq that I’ve written with Stijn van Weezel. This new paper is actually a rejoinder to a reply to an earlier paper I wrote with Stijn which was, in turn, a critique of a still earlier paper. In short, Stijn and I have been in an ongoing discussion about excess deaths in Iraq.
So now is a good time to bring my blog readers into the loop on all this new stuff. Moreover, we are pressed for space in our soon-to-be-published rejoinder so we promise to extend the material onto my blog. This post is the beginning of the promised extension.
Today I’ll set the table by describing the following sequence of publications.
- The starting point is this paper by Hagopian et al. which concludes:
Beyond expected rates, most mortality increases in Iraq can be attributed to direct violence, but about a third are attributable to indirect causes (such as from failures of health, sanitation, transportation, communication, and other systems). Approximately a half million deaths in Iraq could be attributable to the war.
I blogged on this estimate a while back. Back then my point was simply to show how Hagopian et al. start with a data-based central estimate surrounded by massive uncertainty and then seize on one excuse after another to inflate their central estimate and air brush the uncertainty away. They wind up with a much higher central estimate than their data can sustain which they then treat as a conservative lower bound. (The above quote was just a way station along this inflationary journey, delivered in an academic journal that imposed some, but not sufficient, restraint.)
2. Stijn and I publish a critique of the Hagopian et al. paper.
We focus mostly on the weakness of the case for a large number of non-violent excess deaths in the Iraq war, although we do touch on the inflationary dynamics mentioned above.
Before turning to the main highlights of our critique paper let’s quickly review the concept of excess deaths as it pertains to the Hagopian et al. Iraq estimates. Their main claim boils down to saying that the during-war death rate in Iraq is higher than the pre-war death rate there. They then assume that this increase is caused by the war.
There are a few problems with this train of thought.
a. The causal claim commits a known logical error called the “after this, therefore because of this” fallacy. An example would be arguing that “my alarm clock going off causes the sun to rise.”
That said, the notion that the outbreak of war causes all observed changes in death rates afterward is sufficiently plausible that we shouldn’t just dismiss the idea because logic doesn’t automatically imply it.
b. The only reason for invoking the excess-deaths concept in the first place is the idea that war violence might lead indirectly to non-violent deaths that wouldn’t have occurred without the war. To address this possibility we should ask whether the during-war non-violent death rate is higher than pre-war non-violent death rate. Hagopian et al. confound this comparison of like with like by tossing during-war violent deaths into this mix. Thus, they compare during-war violent plus non-violent deaths with pre-war non-violent deaths.
Stijn and I perform appropriate comparisons of non-violent death rates. You can look at the numbers yourself by popping open the paper. But the general picture is easy enough to understand without looking. Our central estimates (under various scenarios) for non-violent deaths are always positive but the uncertainty intervals surrounding these estimates are extremely wide and dip far below zero. Thus, evidence that there are very many, if any, non-violent excess deaths is extremely weak despite the grandiose claims of Hagopian et al..
In our determination to uncover any possible evidence of excess non-violent deaths we also perform a “differences-in-differences” analysis. The idea here is that if violence leads indirectly to non-violent deaths then we’d expect non-violent death rates to jump up more in relatively violent zones than they do in relatively peaceful zones. In other words, if violence leads indirectly to non-violent deaths in Iraq then there should be a positive spatial correlation between violence and increases in non-violent death rates. We find no such thing.
There is more in the paper and I would be delighted to respond to questions about it. But, for now, I’ll move on.
3. Next, Hagopian et al. respond.
I assume that, soon enough, you’ll be able to see their response together with our rejoinder side by side in the journal so I won’t go into detail here. Still, I want to note two things.
First, the Hagopian et al. reply does not address our main point about the separation of violent deaths from non-violent deaths which is described in section 2 above.
Second, Hagopian et al. spill considerable ink on ad hominem attacks. The main one takes of form of saying that I have worked with Iraq Body Count (IBC) and the IBC dataset is bad – therefore nobody should trust anything I say. Stijn and I don’t actually mention IBC in our critique paper so IBC data quality is entirely irrelevant to our argument. Indeed, Hagopian et al. don’t even try to link IBC data quality with any of our substantive arguments. Yet, I fear that much of the mud they sling at IBC will stick so I’ll try to clean some of it off in the follow-up blog posts.
4. Finally, there is our rejoinder.
Again, I don’t want to attempt too much prior to publication. However, as already mentioned above, I will do a few further blog posts on material that we couldn’t cover within the space we had. These will be mainly, possibly exclusively, about the IBC database which Hagopian et al. attack very unreasonably in their reply.
OK, I’ve set the table. More later.