最近，我獲得了極為難得的機會，向四位曾在政府任職的頂尖經濟學家請教當前經濟中困擾我的五個問題。這四位經濟學家分別是本?伯南克、邁克爾?波斯金、約瑟夫?斯蒂格利茨和莫里斯?奧布斯特菲爾德。他們受布魯金斯學會哈欽斯中心主任大衛?韋塞爾邀請，參加了白宮經濟顧問委員會成立70周年慶典。

我提出的五大謎以及四位經濟學家的解答摘要如下：

生產率之謎：如果說出現了新的工業革命，那么生產率為何沒有提高？

四位經濟學家各抒己見，但總的來說，他們提出的原因包括統計數據不準，技術轉化為生產率的提升存在滯后期，以及坦承物聯網的意義或許不像電力那么重大。有人提到了羅伯特?戈登的新書《美國增長率的起伏》。我還沒有拜讀過。誰有時間看一本784頁的書啊？

通脹之謎：失業率低于5%，為何沒有看到通脹？反映失業率和通脹關系的菲利普斯曲線出了什么問題么？

伯南克說，用來表明失業與通貨膨脹反向關系的菲利普斯曲線，可能仍是經濟學家解讀宏觀經濟的最佳框架。奧布斯特菲爾德則指出，對美國來說或許仍然適用，但就全球而言，失業率和通脹之間的關系已經不再遵從菲利普斯曲線。

油價之迷：油價下跌對經濟來說為什么不是件好事？

癡迷于信息不對稱理論的斯蒂格利茨說，價格大幅波動對經濟的影響有好有壞，但看起來短期內不利影響將占據上風。

中國之迷：中國經濟下滑會波及全球經濟的其他領域嗎？

四位經濟學家都認為中國經濟有問題，但伯南克態度樂觀：“好消息是中國政府掌握著大量資源，而且愿意用來維持經濟。”他還指出，中國的大多數債務都是國內債務，而不是外債，因此，中國經濟即便出現問題也不會大范圍傳播。

貧富差距之迷：為何貧富差距越來越大？

不出所料，波斯金和斯蒂格利茨對此爭執不下。波斯金的觀點是全球貧富差距已經變小，發達國家的貧富差距主要源于技術和全球化，而且應該更關注經濟普遍缺乏增長的問題，而不是貧富差距。斯蒂格利茨則引述了托馬斯?皮凱蒂所著《21世紀的資本》中的觀點。不過，這本696頁的書我也沒有讀過。（財富中文網）

譯者：Charlie

審校：夏林

Recently, I had the rare opportunity to quiz four of the smartest economists who have ever served in government – Ben Bernanke, Michael Boskin, Joseph Stiglitz and Maurice Obstfeld – on the five things that puzzle me about today’s economy. The panel was put together by David Wessel of the Hutchins Center at Brookings as part of a celebration of the 70th anniversary of the President’s Council of Economic Advisers.

My five mysteries, and some takeaways:

The productivity mystery: If we are in a new industrial revolution, why isn’t productivity growing?

Lively disagreement on this, but the answer seems to be a combination of bad statistics, long lags in achieving productivity gains from technology, and a recognition that the “internet of things” may not be as big as electricity. Some talk about Robert Gordon’s new book The Rise and Fall of American Growth, which I haven’t read. Who has time for 784 pages?

The inflation mystery: With unemployment below 5 percent, why isn’t there any? What happened to the “Philips Curve” relationship between unemployment and inflation?

Bernanke said the Philips Curve is probably still the best framework economists have to understand the macro economy. Obstfeld says that may be true in the U.S., but globally, the relationship has vanished.

The oil mystery: Why aren’t falling oil prices a good thing for the economy?

Stiglitz, who is fond of asymmetries, said big price movements have both good and bad economic effects, but the bad ones tend to win out in the short term.

The China mystery: Will its problems spill over into the rest of the global economy?

All agree China is a problem, but Bernanke played the optimist: “The good news is that the Chinese government has large resources and is willing to use them.” He also pointed out most Chinese debt is held inside the country, not overseas, limiting contagion.

The inequality mystery: Why is it getting worse?

Boskin and Stiglitz tussled over this one, as expected. Boskin’s argument: that global inequality has fallen; that inequality within developed countries is driven primarily by technology and globalization; and that it’s better to focus on lack of growth overall than on inequality. Stiglitz referred to Thomas Piketty’s book Capital in the Twenty-First Century which, at 696 pages, I also haven’t read.