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Simon Nixon has a provocative article in the WSJ where he argues that the current generation of New Keynesian models are useless because of their poor forecast performance. He proposes looking solely at the rate of debt reduction when forecasting economic performance:

[The] dismal science’s [forecasting] record suggests is that there is something profoundly wrong with the mainstream economics profession’s understanding of how modern economies work. The models on which its forecasts are built are clearly badly flawed.

It is true that forecasting performance is poor, but that is largely because forecasting is very, very difficult. The DSGE models Nixon refers to are important in modern macroeconomics but they were originally designed to estimate the impact of monetary policy, not to forecast the future. In fact, until very recently, most forecasting was not done with structural DSGE models but with statistical models that take their structure from the data. They provided better forecast performance and so were preferred by professional forecasters. These days, the best forecasts tend to be made by estimated DSGE models that outperform the best statistical models because they incorporate some of our understanding about how the economy works. No doubt they will be improved over time but it is incorrect to suggest that forecasters are too constrained by theory to forecast accurately. In fact, economists’ understanding of the economy helps them to provide better predictions about the future than simply using statistical relationships.

Nixon then discusses a paper by Claudio Borio at the BIS, which suggests building models that describe not only business cycles but also ‘financial cycles’. Borio’s paper highlights the monetary nature of the current recession and recommends that the next generation of macro models give serious consideration to the slow buildup of disequilibrium forces in financial booms, which then trigger deep recessions. Whether or not you agree with that diagnosis, the question he tackles is crucial: how do crises endogenously develop? Part of the reason forecasting is so difficult is that turning points are hard to pick because we don’t really understand all of the mechanisms that lead to recessions. Nixon uses that paper to claim that…

…[for] investors, the sensible response is surely to disregard all short-term forecasts based on out-dated models. They should focus instead on identifying those economies most likely to deliver a medium-term recovery by aggressively addressing their stock of debt. In the European context, it is the euro zone where the process of debt reduction and restructuring seems likely to proceed most rapidly, not least because the greater independence of the European Central Bank means there is less prospect of loose monetary policy being used to defer tough decisions.

I don’t think that is what Borio’s paper claims. Can Nixon really be advising you to ignore expert forecasters and instead put your money into EU countries, many of whom are currently facing the possibility of further recession in 2013? He has good company in suggesting that current economic models have problems and could be improved; however, the chances that they can be improved upon by following a simple heuristic like ‘less debt equals more growth’ are exceedingly slim. Indeed, there is considerable public debate among economists over the impact of debt on growth. Reinhart and Rogoff’s work has generated a lot of discussion, and there is a paper entitled ‘Macroeconomic Risk and Debt Overhang’ being presented at the ASSA conference. It’s hardly a matter that has been neglected by the profession!

Of course, it’s very difficult to diagnose and fix a problem with a single newspaper article: witness Paul Krugman’s repeated attacks on the current state of macroeconomics and the heated responses that they’ve generated, for instance. When even Nobel prize-winners can’t agree on whether there is a problem it is a sign that we don’t really understand what needs to be done. It’s great that Nixon is bringing interesting papers like Borio’s to public attention and airing the debate that’s going on in the profession. Unfortunately, in this case I don’t think his diagnosis or proposed solution are quite right.