IS week 2 follow-up: how we model war

With some time on my hands before watching Kentucky brutalize LSU down in Baton Rouge, I want to return to another topic we covered in international security this week: specifically, the choices we make when we model war. This will be a long-running discussion, I think, but we had a question asked about how relevant the group of models we read—which treat war as a costly lottery—are for something other than interstate war.

In line with Thursday’s post, I’d consider that a question worth thinking about. I asked the class what every model we read assumed about a war, and we came down on three things:

  1. war is costly
  2. the outcome is probabilistic
  3. bargaining stops once war begins

When you’re talking about costly lottery models, that’s pretty much it, no? We’ll spend more time during the semester on what it means to relax assumptions 1 (in the leader-centric weeks) and 3 (in the war-as-costly-process week), but we can still say a lot about what the costly lottery assumptions get us in terms of, say, civil/intrastate or extra-state war.

The answer, I think, is quite a lot, though as always it depends on what we’re asking the model to tell us. To the extent that intrastate wars have these features—especially their costliness and the probabilistic nature of the outcome—then we’d expect to see similar dynamics in their causes. That is, discrepancies between the distribution of benefits and the distribution of power, shifting power, private information with incentives to lie—all these things—can lead players to fight a war that has the features of a costly lottery.

Now, there are many differences between the belligerents that fight interstate and intra-state wars, sure—agency problems, enforcement problems, etc. maybe differ across them—and to the extent that we’re interested in those features of intrastate wars, we’d want to model them explicitly. But unless they’d give us profoundly different answers about the effects of, say, shifting power and incentives to misrepresent—and in some cases they very well might—we’ve no need to complicate our models with them unnecessarily. Insurgencies, for example, may have the flavor of players bargaining before a decisive third audience—the public—or wars may have varying degrees of the risk of pure stalemate, etc., and if we want to know about the effects of those features, we build them in…

…but until we get to that point, there’s little wrong with seeing just how much we can translate from one context to another based on the extent to which one simple set of assumptions characterizes both.


2 thoughts on “IS week 2 follow-up: how we model war

  1. I have been thinking about similar issues. Some recent work on contest-success function offer another way to model war, one that doesn’t rely on the bargaining metaphor as much, and are worth further investigating (Skaperdas),
    Another thing I’ve lately been thinking about is where or how we could trace the empirical variation that supposedly drives these models. Where does variation in private info come from? Would it be useful to explore empirically when/whether incentives to misrpresent vary? Certain scholars have done interesting work on the sources of variation in commitment problems …. Also, where does variation in audience costs come from, where I’d be less interested in regime-type attributes and more in temporal variation in audience costs.
    Just my two cents.

    • Hein. Agreed. I’ve been trying to learn more about CSFs lately, too. (I’m finishing a paper for the Texas Triangle conference now that uses one to endogenize both the military balance and the destructiveness of the war, which has been pretty fun.)

      I think I’ll have some more thoughts on the other stuff soon, too…will keep you apprised. 😉

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