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Statistics of Deadly Quarrels

Brian Hayes

Mere Anarchy Loosed upon the World

The residuum of all these noncauses of war is mere randomness—the notion that warring nations bang against one another with no more plan or principle than molecules in an overheated gas. In this respect, Richardson's data suggest that wars are like hurricanes or earthquakes: We can't know in advance when or where a specific event will strike, but we do know how many to expect in the long run. We can compute the number of victims; we just can't say who they'll be.

This view of wars as random catastrophes is not a comforting thought. It seems to leave us no control over our own destiny, nor any room for individual virtue or villainy. If wars just happen, who's to blame? But this is a misreading of Richardson's findings. Statistical "laws" are not rules that govern the behavior either of nations or of individuals; they merely describe that behavior in the aggregate. A murderer might offer the defense that the crime rate is a known quantity, and so someone has to keep it up, but that plea is not likely to earn the sympathy of a jury. Conscience and personal responsibility are in no way diminished by taking a statistical view of war.

Figure 6. Long-term catalogue of global conflicts . . .Click to Enlarge Image

What is depressing is that the data suggest no clear plan of action for those who want to reduce the prevalence of violence. Richardson himself was disappointed that his studies pointed to no obvious remedy. Perhaps he was expecting too much. A retired physicist reading the Encyclopaedia Britannica can do just so much toward securing world peace. But with larger and more detailed data sets, and more powerful statistical machinery, some useful lessons might emerge.

There is now a whole community of people working to gather war data, many of whom trace their intellectual heritage back to Richardson and Quincy Wright. The largest such undertaking is the Correlates of War project, begun in the 1960s by J. David Singer of the University of Michigan. The COW catalogues, like Richardson's, begin in the post-Napoleonic period, but they have been brought up close to the present day and now list thousands of militarized disputes. Offshoots and continuations of the project are being maintained by Russell J. Leng of Middlebury College and by Stuart A. Bremer of Pennsylvania State University.

Peter Brecke of the Georgia Institute of Technology has begun another data collection. His catalogue extends down to magnitude 1.5 (about 30 deaths) and covers a much longer span of time, back as far as a.d. 1400. The catalogue is approaching completion for 5 of 12 global regions and includes more than 3,000 conflicts. The most intriguing finding so far is a dramatic, century-long lull in the 1700s.

Even if Richardson's limited data were all we had to go on, one clear policy imperative emerges: At all costs avoid the clash of the titans. However painful a series of brushfire wars may seem to the participants, it is the great global conflagrations that threaten us most. As noted above, the two magnitude-7 wars of the 20th century were responsible for three-fifths of all the deaths that Richardson recorded. We now have it in our power to have a magnitude-8 or -9 war. In the aftermath of such an event, no one would say that war is demographically irrelevant. After a war of magnitude 9.8, no one would say anything at all.

© Brian Hayes

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