曲奇和牛奶，凱斯·厄本和妮可·基德曼,，Jay-Z和碧昂斯,，他們都有某種持續(xù)的關(guān)系。在經(jīng)濟(jì)學(xué)領(lǐng)域里,，失業(yè)和通脹的關(guān)系也是這樣,。1958年，經(jīng)濟(jì)學(xué)家威廉·菲利普斯觀(guān)察到一種有趣的現(xiàn)象——失業(yè)率下降時(shí),，通脹率好像就會(huì)上升,。這種反向關(guān)系后來(lái)被稱(chēng)為菲利普斯曲線(xiàn)。但最近,，許多經(jīng)濟(jì)分析師和股票市場(chǎng)觀(guān)察人士都在問(wèn),，美國(guó)失業(yè)率已經(jīng)跌破4%，那為什么通脹率還是如此之低（不到2%）呢,？

首先,，菲利普斯實(shí)際上并沒(méi)有說(shuō)失業(yè)率下降時(shí)通脹率就會(huì)上升,。在研究了1861-1957年的數(shù)據(jù)后，他的結(jié)論是失業(yè)率下降時(shí),，工資往往會(huì)上升,。由于通脹率經(jīng)常隨之上行，其他經(jīng)濟(jì)學(xué)家開(kāi)始把失業(yè)率和通脹率之間的相反關(guān)系作為經(jīng)濟(jì)前景的便捷預(yù)測(cè)指標(biāo),，并據(jù)此推斷央行什么時(shí)候會(huì)為了抑制通脹而提高利率,。出于這樣的原因，現(xiàn)在金融行業(yè)已經(jīng)出現(xiàn)了一些關(guān)于菲利普斯曲線(xiàn)為何“不起作用”的討論,。

Cookies and milk. Keith and Nicole. Jay-Z and Beyoncé. There are certain relationships that just seem to last. In the world of economics, it’s unemployment and inflation. Way back in 1958, economist William Phillips made an interesting observation. It seemed as though when unemployment went down, inflation went up. The inverse relationship became known as the Phillips Curve, and recently a lot of economic analysts and stock market watchers have been asking, with unemployment below 4%, why is inflation still so low (under 2%)?

First of all, Phillips didn’t actually say when unemployment fell, inflation would go up. After studying data between 1861 and 1957, he made the observation that when unemployment went down, wages tended to rise. Since inflation often goes up after that, other economists started using the inverse relationship between unemployment and inflation as a short hand predictor of what might happen in the economy—and as a clue as to when central banks might raise interest rates in an effort to keep inflation at bay. This has led to some current discussions in the financial industry as to why the Phillips Curve “isn’t working.”

房利美的首席經(jīng)濟(jì)學(xué)家道格·鄧肯認(rèn)為,，它沒(méi)有“起作用”的原因首先是二者并非因果關(guān)系，“菲利普斯曲線(xiàn)描述的是就業(yè)和通脹之間的關(guān)聯(lián)性,。二者的關(guān)聯(lián)程度因時(shí)而異,，但不會(huì)發(fā)展成因果關(guān)系,?！彼裕m然通脹上升有時(shí)可能出現(xiàn)在失業(yè)率下降的階段,，但它們并非一個(gè)是因一個(gè)是果,。

實(shí)際上二者之間已經(jīng)出現(xiàn)過(guò)很多次例外情況，它們的反向關(guān)系也經(jīng)常受到質(zhì)疑,。舉例來(lái)說(shuō),，在20世紀(jì)70年代，曾經(jīng)出現(xiàn)過(guò)滯漲階段,，即失業(yè)率和通脹率同時(shí)上升,。經(jīng)濟(jì)學(xué)家米爾頓·弗里德曼甚至說(shuō)過(guò)，失業(yè)率和通脹率的反向關(guān)系只在短時(shí)期內(nèi)有效,。就像布拉德·皮特和安吉麗娜·朱莉的婚姻只維持了兩年,。

弗里德曼認(rèn)為，通脹上升時(shí),，工資較低的勞動(dòng)者可能會(huì)突然意識(shí)到自己的工資偏低,，進(jìn)而開(kāi)始要求加薪，或者通過(guò)跳槽來(lái)提高收入,。這就是整體工資水平上升的原因,。但這是個(gè)短期現(xiàn)象；從長(zhǎng)期來(lái)看,，其他許多因素也會(huì)決定通脹是否上升,。

嘉信理財(cái)?shù)氖紫顿Y策略分析師麗茲·安·索德斯指出，目前的決定因素之一就是經(jīng)濟(jì),，其增速一直不足以給工資和通脹帶來(lái)壓力,，“直到去年中期,，名義GDP增長(zhǎng)率仍然低于失業(yè)率。在歷史上,，出現(xiàn)這種情況時(shí),，就不會(huì)發(fā)生菲利普斯曲線(xiàn)所描述的那種關(guān)聯(lián)?！钡f(shuō),，去年年中菲利普斯曲線(xiàn)再次開(kāi)始發(fā)揮作用，“我們終于看到平均時(shí)薪增速略有提高,，只是尚未達(dá)到以往周期后半段4%左右的水平,。”

It doesn’t “work” because it’s not a cause-and-effect relationship to begin with, according to Doug Duncan, Chief Economist at Fannie Mae. “The Phillips Curve is the observation that there is correlation of employment and inflation. The degree of correlation varies over time. But that does not extend to causation.” So while rising inflation may sometimes occur during times of falling unemployment, one doesn’t cause the other.

In fact, there have been so many exceptions to the inverse relationship, its usefulness is often called into question. For instance, there was the period of stagflation in the 70s when unemployment and inflation both went up. And economist Milton Friedman went so far as to state that the inverse relationship between unemployment and inflation only worked in the short term. Kind of like Brad and Angelina. (Sorry.)

Friedman said that when inflation kicked in, workers who were getting paid lower wages would suddenly realize they were being underpaid and start to ask for raises or change jobs to make more money. That’s why overall wages would go up. But this was a short term phenomenon; over the long term, many other factors would affect whether inflation rose.

Liz Ann Sonders, Chief Investment Strategist at Charles Schwab & Co., points to one determining factor right now as the economy, which hasn’t been growing fast enough to put pressure on wages and inflation. “Up until mid-last year, nominal GDP growth was below the unemployment rate. Historically when that occurs, there has been no Phillips Curve correlation.” But in the middle of last year, she says, the Phillips Curve kicked back in. “We finally saw average hourly earnings kick into a slightly higher gear, albeit not to the 4% or so that historically accompanied the latter part of cycles.”

但這次的工資上漲并未帶動(dòng)通脹大幅上升,。剛剛出爐的CPI報(bào)告顯示,，今年5月，美國(guó)通脹率為0.1%,，這讓過(guò)去12個(gè)月美國(guó)CPI降至1.8%的低水平,。

鄧肯認(rèn)為：“勞動(dòng)者的生產(chǎn)率上升了，因此拿到了更高的工資,。這不是通脹,。生產(chǎn)率上升的動(dòng)力來(lái)自于企業(yè)投資，而且當(dāng)前環(huán)境下往往是對(duì)技術(shù)工具的投資,?！?/p>

鑒于菲利普斯曲線(xiàn)描述的關(guān)聯(lián)具有不確定性而且作用范圍較小，央行無(wú)法將其作為可靠的預(yù)測(cè)工具,。就連美聯(lián)儲(chǔ)主席杰羅姆·鮑威爾也在6月初講話(huà)時(shí)提到了菲利普斯曲線(xiàn),，他描述了一個(gè)“和目前情況差不多”的低通脹（1.4%）、低失業(yè)率（4.1%）階段,。鮑威爾說(shuō),，當(dāng)時(shí)的“宏觀(guān)經(jīng)濟(jì)學(xué)家對(duì)菲利普斯曲線(xiàn)呈平直狀態(tài)感到困惑?！彼傅氖?999年,。在那之后的幾年里，互聯(lián)網(wǎng)泡沫破裂,，大衰退也即將到來(lái),。導(dǎo)致大衰退的原因眾多，包括家庭債務(wù),、按揭危機(jī)以及銀行倒閉,。美聯(lián)儲(chǔ)政策所要應(yīng)付的經(jīng)濟(jì)局勢(shì)要比通脹和工資之間的簡(jiǎn)單關(guān)系復(fù)雜得多。

在當(dāng)前經(jīng)濟(jì)中,，鮑威爾關(guān)注的絕不僅僅是菲利普斯曲線(xiàn),?！坝秘泿耪呓o就業(yè)市場(chǎng)施加足夠大的推力從而提高通脹存在讓金融等市場(chǎng)出現(xiàn)不穩(wěn)定過(guò)剩的風(fēng)險(xiǎn)?！睋Q句話(huà)說(shuō),，下調(diào)利率來(lái)刺激經(jīng)濟(jì)在理論上會(huì)帶動(dòng)工資和通脹上升，但也可能產(chǎn)生反作用,。經(jīng)濟(jì)體系中資金過(guò)多可能使經(jīng)濟(jì)過(guò)熱,，而且首先，它形成的局面可能非常類(lèi)似于引發(fā)2008年金融危機(jī)的情況,。

因此,，雖然不能忽視體現(xiàn)失業(yè)率和通脹率關(guān)系的菲利普斯曲線(xiàn)，但如今的情況要比曲奇和牛奶的簡(jiǎn)單關(guān)聯(lián)更復(fù)雜一些,。（財(cái)富中文網(wǎng)）

譯者：Charlie

審校：夏林

But this time while wages have risen, significant inflation has not followed. The just-released CPI report showed a modest .1% rise in May, pushing inflation at the consumer level down to a rate of just 1.8% over the past 12 months.

“Workers are becoming more productive so businesses are paying them more,” according to Duncan. “This is not inflation. The source of the productivity gain is investment by businesses, often in the current environment in technology tools.”

Given the uncertainty and narrow scope of the Phillips Curve correlations, central banks can’t use the curve as a reliable predictive tool. No less than Fed Chairman Jerome Powell referred to the Phillips Curve in a speech at the beginning of June, describing a period of low inflation (1.4%) and low unemployment (4.1%) that was “not so different from today.” It was a time, he said, that “macroeconomists were puzzling over the flatness of the Phillips Curve.” The year was 1999. In the subsequent years, we saw the collapse of the dot.com boom and the onset of the Great Recession, driven by a myriad of causes, including household debt, the mortgage crisis, and bank failures. Fed policy had to react to economic dynamics infinitely more complicated than the simple relationship between inflation and wages.

In the current economy, Powell has his eye on much more than just the Phillips Curve. “Using monetary policy to push sufficiently hard on labor markets to lift inflation could pose risks of destabilizing excesses in financial markets or elsewhere.” In other words, lowering interest rates in order to stimulate the economy, which theoretically would lead to a growth in wages and inflation, could backfire. Too much money in the system could lead to an overheated economy and a scenario much like the one that led to the 2008 financial crisis in the first place.

So while the Phillips Curve relationship between unemployment and inflation can’t be ignored, today’s equation is a little more complicated than just cookies and milk.