质疑耶伦和美联储的五个理由

While I do not believe the Federal Reserve made a serious mistake on Wednesday in raising rates, I believe that the “preemption of inflation based on the Phillips curve” paradigm within which it is operating is highly problematic. Much better would be a “shoot only when you see the whites of the eyes of inflation” paradigm of the kind I have advocated for the last several years.

虽然我不认为美联储(Fed)上周三加息犯了严重错误，但我相信，美联储运行的框架——“基于菲利普斯曲线(Phillips curve)抢先狙击通胀”的策略很有问题。更好的选择是我在过去几年一直倡导的策略：“只在看到通胀的确凿证据时才开枪”。

Such a paradigm would be more credible, more likely to result in the Fed’s satisfying its dual mandate, reduce the risk of recession and increase the economy’s resilience when recession comes.

后一种策略更可靠，更有可能让美联储完成其双重任务——降低出现经济衰退的风险，并增强美国经济在衰退到来时的韧性。

Many of my friends have recently issued a statement asserting that the Fed should change its inflation target. I suspect, for reasons I will write about in the next few days, that moving away from inflation targeting to something like nominal gross domestic product level targeting would be a better idea. But I believe this issue is logically subsequent to the question of how policy should be made in the near term with the given 2 per cent inflation target.

我的许多朋友最近联合发表了一份声明，坚称美联储应改变其通胀目标。我觉得（原因我将在近期再写），从以通胀为目标转向如以名义国内生产总值(GDP)为目标，是个更好的主意。但我认为，这一问题逻辑上应排在如下另一问题之后：在通胀目标被设为2%的情况下，短期政策应如何制定。

Five points frame my doubts about the current approach.

有5点理由支撑我对当前加息策略的质疑。

First, The Fed is not credible with the markets at this point. Its dots plots predict four rate increases over the next 18 months compared with the markets’ expectation of less than two. Table 1 shows the Fed has been highly unrealistic in its forecasts for several years now

首先，眼下美联储在市场眼中并不可信。美联储的“点阵图”预计未来18个月将加息4次，相比之下，市场的预期为不超过两次。从表一可以看出，美联储的预测已有好几年极度脱离实际。

There are some caveats in comparing market and Fed forecasts. Fed chair Janet Yellen is not necessarily the median dot but has disproportionate influence. Additionally, the dots refer to the modal (most likely) rather than the average future scenario. Both those factors might tend to make the Fed forecast overstated, if Ms Yellen is more dovish than the Fed as a whole. But, on the other hand, market forecasts contain term premiums that are on average positive, implying that market expectations for Fed policy should also be biased to the upside. In sum, there is no rationalising away the protracted pattern of Fed forecasting errors except to doubt the models on which the Fed is relying.

比较市场的预测和美联储的预测时应注意一些事项。美联储主席珍妮特?耶伦(Janet Yellen)未必就是中值点，但她拥有其他人不可比拟的影响力。此外，点阵图显示的是众数（最有可能的）、而非平均数的未来场景。如果耶伦比美联储整体更鸽派的话，这两个因素都可能倾向于使美联储的预测偏高。但另一方面，市场预期包含通常为正值的期限溢价，这意味着市场对美联储政策的预期也应偏高。总之，除了质疑美联储依赖的模型，否则美联储持续的预测失误讲不通。

The truth is that markets do not share the Fed’s view that inflation acceleration is a major risk. Indeed, they do not believe the Fed will attain its 2 percent inflation target for a long time to come. Table 2 shows than neither inflation indexed bonds nor the swap market expect the Fed to hit its 2 per cent personal consumption expenditure (PCE) inflation goal in the foreseeable future.

事实上，市场并不认同美联储的如下观点：通胀加速是一项重大风险。实际上，市场认为美联储在未来很长一段时间都不会实现2%的通胀目标。表二显示出，通胀指数化债券和互换市场都预期，在可预见的未来，美联储将不会实现2%的个人消费支出(PCE)通胀目标。

If the Fed were equally behind the curve with respect to rising inflation there would be hysteria among the commentariat. They would be proclaiming that the Fed has to move decisively so as not to be behind the curve. Why should there not be concern about disbelieved forecasts of actions that if taken would push inflation further below target than current forecasts?

如果美联储在加息上同样进度落后，那评论圈将炸开锅。他们将宣称，美联储必须果断行动，以跟上进度。预测中的行动如果付诸实施，将把通胀推至进一步低于目前预测的水平，这些受到外界怀疑的行动预测，为什么没有引发关切？

Second, the Fed regularly proclaims that it has a symmetric commitment to its 2 per cent inflation target. Recoveries do not last forever and when recession comes inflation declines. So why would the Fed want to be projecting only 2 per cent inflation entering the 11th year of recovery with a jobless rate clearly below their estimate of the non-accelerating inflation rate of unemployment (Nairu). Such a prediction is coming after a full decade of sub-target inflation. As shown in the graph below, the PCE core price level is a full 4.3 per cent below where it would be had it risen by the Fed’s target amount over the past decade.

其次，美联储经常宣称，其对2%通胀目标的承诺是“对称”的。复苏不会永远持续，而当衰退到来时，通胀将回落。那么，为什么美联储要预测通胀在复苏的第11个年头只有2%，同时失业率显然低于他们估算的非加速通胀的失业率(Nairu)。在做出这一预测之前，通胀有整整10年未达到目标。如图所示，个人消费支出核心价格水平，比按照过去10年美联储的目标值本应升至的水平低了整整4.3%。

Accordingly, policy should be set with a view to achieving modestly above-target inflation, perhaps 2.3 or even 2.5 per cent, during a boom with the expectation that it will decline during the next recession. A higher inflation target would entail easier policy than is now envisioned.

因此，制定政策时应确立如下目标：在繁荣时期实现适度高于目标的通货膨胀，或许是2.3%，甚至2.5%，因为预期通胀会在下一次衰退时下降。而更高的通胀目标将需要比现在预想的更宽松的政策。

Third, pre-emptive attacks on inflation, like pre-emptive attacks on countries, depend on the ability to judge threats accurately. The truth is we have little ability to judge when inflation will accelerate in a major way. The Phillips curve is at most barely present in data for the last 25 years. And as Staiger, Stock and Watson demonstrated years ago the Nairu, assuming such a thing exists, can only be estimated with extreme imprecision.

第三，对通货膨胀发动先发制人的打击，就像对国家发动先发制人的打击一样，取决于准确判断威胁的能力。但实际上，我们几乎没有能力判断通胀何时将大幅加速。菲利普斯曲线在过去25年的数据里几乎不体现。且正像施泰格(Staiger)、施托克(Stock)和沃森(Watson)数年前所证明的，对非加速通货膨胀失业率——假设其存在——只能作出极度不精确的估测。

At some points these might seem like theoretical arguments. But in recent months both overall and core inflation have come down along with market and survey measures of inflation expectations. The most widely followed inflation measure, the consumer price index, has decelerated from 2.5 per cent inflation in January to 1.9 per cent now. Accordingly, inflation expectations have fallen 0.2-0.3 per cent. This behaviour is contrary to all the Fed staff models.

某些时候这些可能看上去只是理论上的理由。但近几个月来，整体通胀率和核心通胀率双双下降，通胀预期的市场和调查指标也是如此。居民消费价格指数(CPI)这一受到最普遍关注的通胀指标，今年1月份实现2.5%的通胀，现在降至1.9%。相应地，通胀预期也下降了0.2到0.3个百分点。这一走势与所有美联储成员模型相反。

With inflation and inflation expectations below target and declining there would be little case for pre-emption even if inflation above target was a serious problem. But, as we have seen, there are strong reasons for thinking that the Fed should to be consistent with its mandate and let inflation rise above 2 per cent.

由于通货膨胀和通胀预期低于目标且不断下降，即使通胀高于目标是个严重的问题，也没有理由对通胀发起先发制人的打击。但正如我们所见，有充分理由认为，美联储应一以贯之地执行其任务，让通胀升高到2%以上。

Fourth, as I have stressed in my writings on secular stagnation and in arecent conversation with David Wessel, there is good reason to believe that a given level of rates is much less expansionary than it used to be given the structural forces operating to raise saving propensities and reduce investment propensities.

第四，正如我之前在讨论长期停滞的文章中，以及与戴维?韦塞尔(David Wessel)最近一次交谈中所强调的，考虑到能够提高储蓄倾向、减少投资倾向的结构性因素在发挥作用，有充分理由认为，一个给定的利率水平远不如曾经那样具有扩张性。

I am not sure that a 2 per cent funds rate is especially expansionary in the current environment. And I am confident that if the Fed errs and tips the economy into recession the consequences will be very serious given that the zero lower bound on interest rates or perhaps a slightly negative rate will not allow the normal countercyclical response. This, too, counsels a bias towards expansion.

我不确定在目前环境下，2%的联邦基金利率算不算特别具有扩张性。而且我确信，如果美联储犯错导致经济陷入衰退，后果将是非常严重的，因为利率的零下限或轻微的负利率都无法为正常的反周期应对提供空间。基于这一点，也应该让联邦基金利率偏向扩张性。

Fifth, a “whites of their eyes” paradigm does not require the Fed to abandon its connection to price stability. It simply needs to assert that its objective is to assure that inflation averages 2 per cent over long periods. Then, it needs to acknowledge that while inflation is persistent, it is very difficult to forecast and signal that it will focus on inflation and inflation expectations data rather than measures of output and employment in forecasting inflation.

第五，“看到通胀的确凿证据时才开枪”模式，不要求美联储放弃与价格稳定的关联。美联储只需坚持，其目标是确保通胀的长期均值为2%。接下来，它需要承认，虽然通胀持续存在，但很难预测通胀，并暗示它在预测通胀时，将把重点放在通胀以及通胀预期数据，而不是产出及就业指标上。

With these principles internalised, the Fed would lower its interest rate forecasts to those of the market and be more credible. It would allow inflation to get closer to target and give employment and output more room to run.

纳入这些原则后，美联储会把其利率预测降至与市场预测持平，会变得更可信。它会容许通胀处于离目标更近的水平，并为就业和产出提供更多空间。