Nobel laureate Robert Lucas has penned a column defending macroeconomists against two recent Economist articles. In so doing, he discusses the recession, the financial crisis, the efficient market hypothesis (EMH), and why economists did not forecast the severe downturn. If you want to read the Economist articles to which he is referring, see here and here. An excerpt.
Mr Fama arrived at the EMH through some simple theoretical examples. This simplicity was criticised in The Economist’s briefing, as though the EMH applied only to these hypothetical cases. But Mr Fama tested the predictions of the EMH on the behaviour of actual prices. These tests could have come out either way, but they came out very favourably. His empirical work was novel and carefully executed. It has been thoroughly challenged by a flood of criticism which has served mainly to confirm the accuracy of the hypothesis. Over the years exceptions and “anomalies” have been discovered (even tiny departures are interesting if you are managing enough money) but for the purposes of macroeconomic analysis and forecasting these departures are too small to matter. The main lesson we should take away from the EMH for policymaking purposes is the futility of trying to deal with crises and recessions by finding central bankers and regulators who can identify and puncture bubbles. If these people exist, we will not be able to afford them.
The Economist’s briefing also cited as an example of macroeconomic failure the “reassuring” simulations that Frederic Mishkin, then a governor of the Federal Reserve, presented in the summer of 2007. The charge is that the Fed’s FRB/US forecasting model failed to predict the events of September 2008. Yet the simulations were not presented as assurance that no crisis would occur, but as a forecast of what could be expected conditional on a crisis not occurring. Until the Lehman failure the recession was pretty typical of the modest downturns of the post-war period. There was a recession under way, led by the decline in housing construction. Mr Mishkin’s forecast was a reasonable estimate of what would have followed if the housing decline had continued to be the only or the main factor involved in the economic downturn. After the Lehman bankruptcy, too, models very like the one Mr Mishkin had used, combined with new information, gave what turned out to be very accurate estimates of the private-spending reductions that ensued over the next two quarters. When Ben Bernanke, the chairman of the Fed, warned Hank Paulson, the then treasury secretary, of the economic danger facing America immediately after Lehman’s failure, he knew what he was talking about.
HT Eric Parsons.