What the ‘macroeconomic ideas develop as a response to crises’ story leaves out is the rest of economics, and ideology. The Keynesian revolution (by which I mean macroeconomics after the second world war) can be seen as a methodological revolution. Models were informed by theory, but their equations were built to explain the data. Time series econometrics played an essential role. However this appeared to be different from how other areas of the discipline worked. In these other areas of economics, explaining behaviour in terms of optimisation by individual agents was all important. This created a tension, and a major divide within economics as a whole. Macro appeared quite different from micro.
The New Classical revolution was in part a response to that tension. In methodological terms it was a counter revolution, trying to take macroeconomics away from the econometricians, and bring it back to something microeconomists could understand. Of course it could point to policy in the 1970s as justification, but I doubt that was the driving force. I also think it is difficult to fully understand the New Classical revolution, and the development of RBC models, without adding in some ideology.

上記引用部の冒頭で触れられている“「マクロ経済学の概念は経済危機への反応として発展する」というストーリー”は、Free ExchangeのM.C.K.ことMatthew Kleinが書いたマクロ経済学小史*2、および、それを受けたノアピニオン氏のエントリにおけるマクロ経済学史観を指している。レン−ルイスは、その史観によれば今般の経済危機に対応してマクロ経済学にまた根本的な修正が起こるはずだが、その動きは見られない――せいぜいDSGEに金融摩擦がいろいろ付け加えられたくらい――ではないか、と指摘している。


Noah Smith 24 January 2013 21:25
Well, this still leaves my main question unanswered...Why aren't macroeconomists dissatisfied with our actual inability to tell which models work when (and thus which to use when)?

Mainly Macro 25 January 2013 03:31
Noah - I agree, but my point was that it was not always so. When central banks used models based on time series econometrics, the idea was to explain the data as far as possible. Good empirical work attempted to encompass previous findings. Before RBC, even people writing theory papers would appeal to time series evidence as well as theory in justifying the relationships they used, and there were many more attempts in the literature to estimate consumption functions, investment functions and the like.

Now this did not stop macro making big mistakes, as the 1970s showed. But the current attitude to models and evidence is the result of a particular methodology, and is absolutely not inherent to macro.




*2:同記事は(池尾和人氏もツイートした)プリンストンのMarkus BrunnermeierとDelwin Olivanのスライドをベースにしている。