9/30エントリで紹介したFRBのJeremy B. Rudd論文が経済学界にそれなりの波乱を巻き起こしているようで、タイラー・コーエンが批判的に取り上げるとともに、同論文を紹介したNYT記事や、ジョセフ・ギャニオンリカルド・ライスツイッターでの反応にリンクしている。

As usual,
puts his finger on the most interesting economic controversy of the day. This time it is Fed staffer Jeremy Rudd’s attack on the fetishization of measures of inflation expectations as drivers and predictors of actual inflation. 1/n
I agree with much of what Jeremy says and what my colleague
says in Neil’s article. Yet I also think inflation expectations matter, as do they, I suspect. How to square that circle? 2/n
It boils down to what one means by the word “expectation.” Rudd is criticizing those who believe that firms and workers have strong views about the future path of inflation grounded in a solid understanding of the global forces at work and how policy makers will respond. 3/n
In such a world, getting a good handle on what expectations are becomes a very important guide to policy makers because inflation is largely self-generating. Policy must act to prevent expectations from spiraling out of control. 4/n
I don’t share that view. I think expectations are shaped importantly by the present and the past. To the extent that people do look forward, it is with great uncertainty and little conviction. Views on the future are not firmly held and can change quickly. 5/n
In that world, policy makers should care less about measures of expectations and more about achieving their objectives for actual inflation. Success breeds success. As people see that deviations from target are quickly corrected they worry less and less about runaway prices. 6/n
Given that inflation was a bit below target on average since 2009, the recent overshooting is to be welcomed because it prevents expectations from settling in too low. But the fear that expectations will suddenly zoom upward and cause prolonged inflation is misguided. 7/n
Major shifts in expectations follow shifts in actual inflation, not vice versa, as Madi Sarsenbayev and I showed in a series of recent blog posts. n/n


Mr. Rudd argues that there is no solid evidence that the conventional story of the 1970s describes the real mechanism through which inflation takes place. He says there’s a simpler explanation consistent with the data: that businesses and workers arrive at prices and wages based on the conditions they’ve experienced in the recent past, not some abstract future forecast.
For example, when inflation has been low in the recent past, workers might not demand raises as they would in a world where inflation was high; after all, their existing paychecks go pretty much as far as they used to. You don’t need some theory involving inflation expectations to get there.
Some economists who are sympathetic to the idea that central bankers have overly fetishized precise measurements of inflation expectations aren’t ready to fully dismiss the idea.
For example, Mr. Posen, a former Bank of England policymaker, says there remains a simple and hard-to-dispute idea about inflation expectations supported by lots of history: that if people distrust a country’s monetary system, inflation shocks can spiral upward. Economic policy credibility matters. But that isn’t the same as assuming that some survey or bond market measure of what will happen to inflation in the distant future is particularly meaningful for forecasting the near future.