2018年经济学人 六大经济学原理:新凯恩斯主义(1)（在线收听）

That proposition was put to the test after Paul Volcker became Fed chairman in 1979.

这种主张在保罗·沃克尔于1979年成为美联储主席后被付诸验证。

Mr Volcker was set on getting inflation down.

当时，沃克尔决心要把通胀降下来。

As it turned out, he would need to prove his mettle.

局势的发展表明，他必需证明自己的魄力。

His tight monetary policies—the federal funds rate reached almost 20% in 1981—contributed to a double-dip recession, which pushed unemployment above 10%.

他的收紧的货币政策——联邦利率在1981年达到了将近20%——创造了一次双底衰退，把失业率推到了10%以上。

It got the job done; inflation tumbled.

任务完成了；通胀大幅回落。

Since Mr Volcker's time at the Fed, it has rarely exceeded 5%.

自沃克尔的美联储时代以来，通胀几乎没有超过5%。

To this day, some economists point to the Volcker recessions as proof that inflation expectations are adaptive.

时至今日，有些经济学家认为，沃克尔衰退是通胀预期是自适应的证明。

The public did not believe inflation would fall just because the Fed said it would.

公众没有仅仅因为美联储发话就相信通胀会降下来。

America had to suffer high unemployment to bring inflation down.

为把通胀降下来，美国不得不承受了高失业之苦。

Policymakers had to grapple with a short-term Phillips curve after all, as Friedman and Phelps had argued.

正如弗里德曼和菲尔普斯所言，决策者毕竟还得抓住短期菲利普斯曲线不放。

Yet the experience of the 1980s would not be repeated.

然而，上世纪80年代的这段经历不会再重蹈覆辙了。

In the decades that followed, central banks committed to inflation targets.

在随后的几十年间，各国央行对通胀目标作出了承诺。

As they gained credibility, the trade-off between inflation and unemployment weakened.

随着它们赢得了信誉，通胀和失业之间的那种取舍弱化了。

Economists wrote “New Keynesian” models incorporating rational expectations.

经济学家们给出了体现理性预期的“新凯恩斯主义”模型。

By the mid-2000s some of these models showed a “divine coincidence” : targeting the best possible path for inflation, after an economic shock, would also result in the best possible path for unemployment.

到本世纪头十年中期，有些模型展现出了一种“神一般的巧合”：在某次经济冲击后，瞄准最可能的通胀路径也会导致最可能的失业路径。

Few economists think the divine coincidence holds in practice.

很少有经济学家认为，这种神一般的巧合在实践中站得住脚。

New Keynesian models usually struggle to explain reality unless they are tweaked to incorporate, for example, at least some people with adaptive expectations.

通常情况下，新凯恩斯主义模型都是力争解释现实，除非是为了至少也要把某些有理性预期的人起码也纳入其中而接受微调。

A cursory examination of the data suggests expectations follow inflation (they sank, for instance, after oil prices fell in late-2014).

对数据的粗率梳理表明，预期紧随通胀(例如，它们在油价于2014年年末下跌之后一路下滑。)