Thursday, February 10, 2011

Two quick links - Krugman edition

Paul Krugman is the ultimate polarising force. People either love him or loathe him. I suppose that's what comes with the territory when you are, arguably, the world's most high profile economist.

Anyway, seeing as I referred to him in my previous posts on climate change and food prices, here are two links that seem kinda relevant.

1) Roger Pielke Jr has a post criticizing Paul Krugman's citiation of extreme weather events in which he questions any causation between long-run carbon levels and food prices. I left a comment saying, among other things, that I regard his invocation of the historical food record as tempting the gods of false equivalence. I also think that he's being uncharitable in his basic reading of Krugman's argument. Still, it's an interesting debate with thought-provoking points raised on both sides... I'd especially like to see whether more people pick up on my comments about Norman Borlaug and the possibilities of another "Green Revolution".

2) Back to PK himself, who, in commenting on the American Economic Review's "Top 20" papers of the last 100 years, had this to say:
It’s also worth noting that a number of the papers on the list involve very simple, intuitive models — that includes Friedman on the natural rate, Krueger on rent-seeking, Mundell on currency areas; Shiller’s great piece on stock volatility was also a remarkably simple concept yielding a powerful insight. My own paper was actually pretty math-heavy; uncharacteristically, it’s also a paper in which doing the math fundamentally changed my mind about things (I didn’t believe the home market effect was real until it popped out of the equations; only then did I realize it was obvious.)
Hmmm. Sounds kinda familiar...
Further, and I would say more importantly, [maths] enables us to fully work through the consequences and dynamics of [economic] relationships. Our intuition may suggest certain outcomes, but intuition can be pretty limited in scope. Working through a set of equations enables you to arrive at a final result with a cool clarity, which may then show up unexpected results that only become “intuitive” upon further reflection.



  1. Lots of people are vastly over-interpreting that Krugman article. The link between food shortages, prices, and social unrest should be extremely obvious. The link between climate change and severe weather (I think, although it's not my expertise) is obvious. The link between food production and weather - I thought - was obvious. These seem like a few quite reasonable points to make.

    People are going nuts because they think he's saying severe weather in the last two years "proves climate change", or that he's predicting some kind of starvation doomsday. I think all of these are a little too strenuous.

  2. On the math - this past fall I was at a conference with Richard Freeman and I was talking to him after dinner. He told me something I think you'd like.

    He said that whenever you see anything by him where the math is extremely dense, he's probably talking about something he's not very confident about or that he fully understands yet. He said that when he starts to think about a problem he writes it all down formally. As he continues to work through it the math becomes more elegant and readable and he is able to focus on the key elements of the model. When you come across a paper of his that is easily readable it's usually a more mature idea. He's fully digested the insights from the math so he can express the intuition in words, and he's also had the opportunity to clean up the model a little. But he only gets there by thinking the models through several times and trying to figure out the intuition behind the model.

  3. Thanks Dude,

    Whenever I link to these maths posts, I cringe just a little because I'm not trying to be the flag bearer for a movement or anything. If nothing else, I'm just too damn thick!

    But I like to think that I've got my main point across and, you're right, I do like that Richard Freeman "quote" for very related reasons. I'm mostly interested in choosing the best tools at your disposal to a) analyse the problem, and b) convey your idea to other people.

  4. It has become trendy to be down on math lately. It's always good to challenge that. I'm hardly an adequate mathematical theoretician. My statistics/econometrics is better. But there's gotta be some push-back against this meme.


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