作为美联储主席的伯南克，实在是很委屈。近期，他比任何央行行长都更加积极的作出努力，试图使用货币政策刺激经济。他已经将短期利率调低到了极限水平并采用了创新性货币宽松办法。并且，他一次又一次地重申，通胀压力能够被控制，他的主要担忧在于美国常年居高不下的失业率，但激进派经济学家仍然围攻伯南克，认为他做的还远远不够。
他们希望伯南克提高目标通胀率。但是这将与美联储的立场背道而驰，后者一直努力说服公众相信它将把通胀维持在2%左右的水平。这一立场的可信度是美联储采取积极举措的基础：很难想象，美联储将其资产负债表扩张到让公众不再相信其通胀目标的程度会怎么样。既然如此，那些经济学家为什么还希望美联储牺牲掉好不容易才得来的成果呢？
答案在于他们对持续高失业率原因所在的看法，即：过高的真实利率。此逻辑一点不难：2008年金融危机爆发以前，消费者利用上涨的房价大量举债，以支撑美国的需求。如今，这些负债累累的家庭不再能够通过借钱应付日常开销了。
总需求的大头来源早已消散。而当前消费者的消费热情不高，经通胀调整过后的真实利率本应下降，以鼓励拮据家庭增加支出。但真实利率并没降得足够，因为名义利率不可能低于零。美联储可通过增加通胀率将真实利率拉低到远低于零的水平，从而强迫拮据家庭停止储蓄、开始消费。随着需求的增加，企业也会开始招聘新人，一切都会随之慢慢的好起来。
与以损失投资者的利益为代价，将通胀作为降低长期债务的方法相比，这是一个完全不同的逻辑，但一样的是，都不靠谱。首先，低利率在信贷宽松的时候兴许能够刺激支出，但在当前这样的大环境下传统储蓄者究竟会不会出去消费并不好说。以临近退休的储户为例说明，他们储蓄，只是为了存储足够的金钱以备养老。自2007年以来，储蓄的回报率低得可怜，而利率持续走低倒更有可能促使他们把手头的钱变成存款。
或者，低利率也可能促使他们将自己的退休养老金拿来购买高风险长期债券。这些债券的定价较为激进，当利率最终开始升高时，买入操作极有可能为他们招来损失。纵观分析，当前的美国，很可能正是处在一个失业率严重、退休潮袭来的两难境地。
另外，我同事苏菲（Amir Sufi）与合著者米安（Atif Mian）也指出，美国家庭的债务繁重及需求减少也都是本地性的。拉斯维加斯的发型师之所以会沦落到没有饭碗，部分原因就在于那些家庭需要在房地产消费方面承受繁重的债务，也有一部分当地的建筑工人和地产经纪人因此失业。但即使我们通过什么强制性的措施诱导无债储户增加消费，也没法保证拉斯维加斯有这样一个群体。
如果这些无债一身轻的储户在纽约生活——那里并没经历过什么大规模的兴衰变迁——那么真实利率的降低将能鼓励已然充足的纽约市理发支出，但不能鼓励严重不足的拉斯维加斯理发支出。换句话说，即使真实利率能起作用，作为一种刺激工具，它也不够精准。
最后，我们对公众如何预知央行以后的行动毫不知情。一旦美联储宣布可以接受4%的通胀率，那民众一定会把这当作是美联储高调作秀，抑或觉得通胀目标可以提高一次，必然能够提高二次。民众会不会将通胀率提高作为预期的内容，或者增加债券风险性，或影响长期利率。美国究竟该经历怎样的经济萧条才能够将通胀推回正确的轨道？
其实，负利率是否就是美国高失业率的根源所在，我们还不得而知。但无论如何，我们绝不能够对这样惊心的数字听之任之。或许，为了减轻困难家庭的负债压力，降低利率已提高融资能力，对借款者因房价暴跌而导致无力偿债的情况给予一定的按揭债务减免等，都可以成为一种合理的方法。在这两种方案的作用下，美国普通家庭的债务会得到一定程度而下降。但还有一点也至关重要，想要真正实现可持续的复兴之路，不可以将国家财政恢复到危机爆发前的开支水平，这样不会带来好的作用，相反还会影响建筑业及金融业的可持续增长。
据了解，美国当前储蓄率大约只在GDP的4%左右水平，这样算下来，美国普通家庭的储蓄情况并不富余。怎样做才能改善当前的问题？我想，也许真正有效的举措是提高国民劳动能力，保证他们都有一份稳定的工作及收入。实现这一伟大目标不是朝夕之事，但是，我坚信这是最好的处方！
Poor Ben Bernanke! As Chairman of the United States Federal Reserve Board, he has gone further than any other central banker in recent times in attempting to stimulate the economy through monetary policy. He has cut short-term interest rates to the bone. He has adopted innovative new methods of monetary easing. Again and again, he has repeated that, so long as inflationary pressure remains contained, his main concern is the high level of US unemployment. Yet progressive economists chastise him for not doing enough.
What more could they possibly want? Raise the inflation target, they say, and all will be well. Of course, this would be a radical departure for the Fed, which has worked hard to convince the public that it will keep inflation around 2%. That credibility has allowed the Fed to be aggressive: it is difficult to imagine that it could have expanded its balance sheet to the extent that it has if the public thought that it could not be trusted on inflation. So why do these economists want the Fed to sacrifice its hard-won gains?
The answer lies in their view of the root cause of continued high unemployment: excessively high real interest rates. Their logic is simple. Before the financial crisis erupted in 2008, consumers buoyed US demand by borrowing heavily against their rising house prices. Now these heavily indebted households cannot borrow and spend any more.
An important source of aggregate demand has evaporated. As consumers stopped buying, real (inflation-adjusted) interest rates should have fallen to encourage thrifty households to spend. But real interest rates did not fall enough, because nominal interest rates cannot go below zero. By increasing inflation, the Fed would turn real interest rates seriously negative, thereby coercing thrifty households into spending instead of saving. With rising demand, firms would hire, and all would be well.
This is a different logic from the one that calls for inflation as a way of reducing long-term debt (at the expense of investors), but it has equally serious weaknesses. First, while low rates might encourage spending if credit were easy, it is not at all clear that traditional savers today would go out and spend. Think of the soon-to-retire office worker. She saved because she wanted enough money to retire. Given the terrible returns on savings since 2007, the prospect of continuing low interest rates might make her put even more money aside.
Alternatively, low interest rates could push her (or her pension fund) to buy risky long-maturity bonds. Given that these bonds are already aggressively priced, such a move might thus set her up for a fall when interest rates eventually rise. Indeed, America may well be in the process of adding a pension crisis to the unemployment problem.
Second, household over-indebtedness in the US, as well as the fall in demand, is localized, as my colleague Amir Sufi and his co-author, Atif Mian, have shown. Hairdressers in Las Vegas lost their jobs partly because households there have too much debt stemming from the housing boom, and partly because many local construction workers and real-estate brokers were laid off. Even if we can coerce traditional debt-free savers to spend, it is unlikely that there are enough of them in Las Vegas.
If these debt-free savers are in New York City, which did not experience as much of a boom and a bust, cutting real interest rates will encourage spending on haircuts in New York City, which already has plenty of demand, but not in Las Vegas, which has too little. Put differently, real interest rates are too blunt a stimulus tool, even if they work.
Third, we have little idea about how the public forms expectations about the central bank’s future actions. If the Fed announces that it will tolerate 4% inflation, could the public think that the Fed is bluffing, or that, if an implicit inflation target can be broken once, it can be broken again? Would expectations shift to a much higher inflation rate? How would the added risk premium affect long-term interest rates? What kind of recession would the US have to endure to bring inflation back to comfortable levels?
The answer to all of these questions is: We really don’t know. Given the dubious benefits of still lower real interest rates, placing central-bank credibility at risk would be irresponsible.
Finally, it is not even clear that the zero lower bound is primarily responsible for high US unemployment. Traditional Keynesian frictions like the difficulty of reducing wages and benefits in some industries, as well as non-traditional frictions like the difficulty of moving when one cannot sell (or buy) a house, may share blame.
We cannot ignore high unemployment. Clearly, improving indebted households’ ability to refinance at low current interest rates could help to reduce their debt burden, as would writing off some mortgage debt in cases where falling house prices have left borrowers deep underwater (that is, the outstanding mortgage exceeds the house’s value).
More could be done here. The good news is that household debt is coming down through a combination of repayments and write-offs. But it is also important to recognize that the path to a sustainable recovery does not lie in restoring irresponsible and unaffordable pre-crisis spending, which had the collateral effect of creating unsustainable jobs in construction and finance.
With a savings rate of barely 4% of GDP, the average US household is unlikely to be over-saving. Sensible policy lies in improving the capabilities of the workforce across the country, so that they can get sustainable jobs with steady incomes. That takes time, but it might be the best option left.
