卡在中等收入陷阱？不存在的！_風聞

《世界報業辛迪加》3月27日刊登耶魯大學教授、摩根士丹利亞洲區前主席斯蒂芬·羅奇文章《中國沒有落入中等收入陷阱》

文：Stephen Roach

譯：馬力

長期以來，人們一直對中國有一個很固定的印象，那就是中國是一個經濟快速增長的國家，這種固有印象的產生當然是有原因的。對於一個像中國這樣大的經濟體來説，幾十年如一日保持年經濟增速在10%以上，這在全世界來説是個前所未有的現象，而中國卻做到了：從1980到2011年，中國經濟一直在高速增長。然而如今這個奇蹟似乎就要無法延續了。2012年以後，中國的經濟增速下滑到了7.2%，而最近李克強總理在其年度《政府工作報告》中把對2019年中國經濟的增長目標調到了6%-6.5%。

對於那些看衰中國的人們來説，這的確是一個頗為得意的時刻。畢竟，中國總理的增長目標下限6%意味着2019年的中國經濟增速與當年高速增長時代相比可能會下降40%之多。這使得那些關於“中國將落入中等收入陷阱”的預測聽起來越發有道理了，這個“陷阱”意味着中國這樣一個經濟高速增長的發展中國家在快要接近高收入國家門檻時會突然落入低速增長的軌道。關於這一經濟現象的初步研究顯示：當一個國家的人均收入達到1.6萬-1.7萬美元（這是根據購買力平價標準換算後得出的數據）這個區間時，預期將出現2.5個百分點的經濟增速下降。根據國際貨幣基金組織（IMF）的數據，中國的人均收入在2017年進入了這個區間，而中國在2011年之後已出現增速下降，這就更加令人悲觀了。

在我攻讀經濟學的學生時代，我學到的第一個道理就是要謹慎對待數據分析的結果，其中可能隱藏着嚴重的錯誤。而“中等收入陷阱”就是一個處理大量數據後得出錯誤結論的典型例證。其實，只需一個數據庫和一台性能強大的計算機，我就能“證明”任何一個以“分析性假説”的面目示人的經濟理論。如今“中國已落入中等收入陷阱”的説法廣為流傳，而我在這裏要提出五點來反駁這一説法。

首先，“中等收入陷阱”這個概念本身可能就是不成立的。“中等收入陷阱”這一概念是蘭特·普里切特（Lant Pritchett）和勞倫斯·薩默斯（Lawrence Summers）對全球125個經濟體在1950年至2010年這個時間段的經濟表現進行實證研究後提出的。不過他們能得出的最可靠的結論應該僅限於“經濟發展本身有增速的不連續性和向均值迴歸（譯註：根據“均值迴歸理論”，經濟增速、房產價格等社會現象以及氣温、降水等自然現象，無論高於或低於均值，都會表現出以很高的概率向均值迴歸的傾向。根據該理論，上漲或者下跌的趨勢不管其延續的時間有多長都不可能永遠持續下去，均值迴歸的規律最終一定會應驗）的強烈傾向（a strong tendency for growth discontinuities and mean reversion）”。最近在北京舉行的中國發展高層論壇上，薩默斯在分析快速增長的發展中經濟體可能面臨哪些結果時進一步發展了自己的理論，他認為一些國家出現的均值迴歸放緩現象只不過體現了經濟本身有一種縮小“後奇蹟差距”的傾向（a tendency to close a post-miracle gap）。很顯然，這種週期性增長不連續現象的統計規律（the statistical regularity of such periodic growth gaps）與增長陷阱的長期困境（the permanent quagmire of a growth trap）是截然不同的兩個概念。

第二點，人均收入1.6萬-1.7萬美元的陷阱門檻也許是一個看起來很有道理的表述，然而在動態的全球經濟中，這一表述並沒有特別大的意義。自2012年有關中等收入陷阱的早期研究結果發表以來，全球經濟的規模已經增長了約25%，中等收入陷阱的門檻很可能也會隨之水漲船高。正是由於這個原因，最近的研究表明，即便存在中等收入陷阱，這個陷阱也不應用一個絕對的收入數字來衡量，而是應該用發展中經濟體相對於高收入經濟體的趨近程度來定義。從這個角度來分析，當發展中經濟體的人均收入接近高收入經濟體的20%-30%時，危險會逐漸逼近。考慮到2019年中國按購買力平價標準計算的人均GDP將達到美國的30%左右，現在是時候開始擔心了！

第三點，不應該用同樣的標準來看待所有的增長放緩現象。一個國家的GDP總額是多個部門、多個產業、多種產品的製造活動的總結果。中國各個行業發生的結構性轉變可能會造成增長不連續的表象，而這一表象也許只不過是經過深思熟慮的再平衡戰略的結果。考慮到中國正從高速增長的製造業等第二產業轉向增長相對較慢的服務業等第三產業，如今中國經濟的表現正符合上面的表述。從某種程度上來講，這種轉變是中國再平衡戰略的預期結果，增長有所放緩不應引起過於嚴重的憂慮。

第四點，中國經濟增速放緩是意味着中國已落入“中等收入陷阱”還只是一種單純的增長不連續現象？我想在當前中國經濟發展遭遇的嚴峻挑戰面前，這些都並不重要。在追上佔據技術高地的發達經濟體之後，中國會變成一個怎樣的經濟體？這就是為何中國會決意從引進技術轉向走自主創新之路的原因。對於一個尋求進軍科技前沿的發展中經濟體來説，中等收入與高收入之間的差別不過是相對的（middle-income versus high-income status is a relative comparison）。儘管週期性的外部干擾（如去槓桿、全球經濟放緩甚至貿易戰等）會產生暫時影響，然而若能追趕佔據技術高地的發達經濟體並加入其中來共同推動科技進步，中國終將獲得回報。中國領導人已經在“使中國在2050年之前晉升為一個高收入經濟體”的目標闡述中涵蓋了上述內容。

最後一點，當你着眼於一個國家的長期發展前景時，生產率增長要遠比GDP增長更加重要。因此，我更擔心中國會陷入生產率增長陷阱，而不是GDP增長陷阱。不過，中國的一個研究團隊最近對中國全要素生產率進行的一項研究可以緩解我們的焦慮。與普里切特和薩默斯的研究結果一樣，這項對中國全要素生產率的最新研究也揭示了中國在過去40年裏的一些增長不連續現象。不過在過去5年裏，中國全要素生產率的發展趨勢是令人滿意的：年均增長率約為3%，其中第三產業的全要素生產率增長尤為強勁。因此，儘管最近總體GDP增長在放緩，但由服務業引領的中國經濟再平衡卻正在對整體經濟的生產率增長產生意義重大的積極影響。

現在的問題是中國是否能夠維持其全要素生產率繼續增長（考慮到中國日益強大的自主創新能力以及由不斷壯大的受過良好教育的勞動力所支撐的服務業的持續增長，中國全要素生產率繼續增長的可能性是非常大的）並享受資本存量持續增加帶來的好處。中國這項最新的研究顯示，如果能夠做到這兩點，那麼中國在未來5年內的潛在經濟增長率就會保持在6%左右。這樣一種結果將非常符合中國的長期抱負。

我們可以説：是的，中國經濟增長率10%的時代已經結束了，這也是不可避免的。然而我們有充分的理由相信，中國經濟增長正在從量變轉向質變，這才是故事真正的精彩之處。這意味着，面對“落入中等收入陷阱”的普遍擔憂，中國大可以無視其存在。

No Middle-Income Trap for China

There has always been a fixation on Chinese economic growth. And with good reason. For a large economy, sustaining annual growth rates of 10% over several decades is unprecedented. And yet that’s exactly what China did from 1980 to 2011. But now the miracle is over. Since 2012, annual growth has slowed to 7.2%, and Premier Li Keqiang’s recent annual “work report” set a growth target of just 6-6.5% for 2019.

For the vast legions of China doubters, this is a “gotcha” moment. After all, the lower bound of the premier’s target implies a 40% deceleration from the “miracle” trend. This seems to vindicate warnings of the dreaded “middle-income trap” – the tendency of fast-growing developing economies to revert to a much weaker growth trajectory just when they get their first whiff of prosperity. The early work on this phenomenon was precise in terms of what to expect: as per capita income moved into the $16,000-$17,000 range (in 2005 dollars at purchasing power parity), a sustained growth deceleration of around 2.5 percentage points can be expected. With China having hit that income threshold in 2017, according to International Monetary Fund estimates, its post-2011 slowdown looks all the more ominous.

But one of the first things taught to economics graduate students, even back in my day, is to be wary of the perils of data mining. And the middle-income trap is a classic example of the pitfalls of endless number crunching. Give me a database and a powerful computer, and I can “validate” almost any economic relationship masquerading as an analytical conjecture. There are five key reasons to dismiss the now-widespread diagnosis that China is ensnared in the middle-income trap.

First, a middle-income trap may not even exist. That is the conclusion of Lant Pritchett and Lawrence Summers’s rigorous empirical study covering a broad cross section of 125 economies from 1950 to 2010. The best they could come up with is a strong tendency for growth discontinuities and mean reversion. At the recent China Development Forum in Beijing, Summers went further in assessing likely outcomes in rapidly growing developing economies, dubbing any mean-reverting slowdown as merely a tendency to close a “post-miracle gap.” Needless to say, the statistical regularity of such periodic growth gaps is very different from the permanent quagmire of a growth trap.

Second, a fixed trap threshold of $16,000-$17,000 may be a great literary device, but it makes little sense in a dynamic global economy. Since early research on the middle-income trap was published in 2012, the world economy has grown by about 25% – presumably boosting the moving target of a middle-income threshold by a comparable magnitude over that period. Largely for that reason, recent research has couched the trap not in terms of an absolute threshold, but as relative convergence to high-income countries. From this perspective, danger looms when developing economies’ per capita income approaches 20-30% of the level in high-income economies. Given that China will hit about 30% of America’s per capita GDP (in PPP terms) in 2019, it must be time to worry!

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Third, not all growth slowdowns are alike. A country’s GDP is a broad aggregation of a multiplicity of activities across sectors, businesses, and products. Structural shifts from one sector to another can give the appearance of a growth discontinuity that may be nothing more than the outcome of a deliberate rebalancing strategy. This is very much the case with China today, given its shift from higher-growth manufacturing and other “secondary” industries to slower-growing services, or “tertiary” industries. To the extent that this shift is the intended result of China’s strategic rebalancing, a growth slowdown is far less alarming.

Fourth, the daunting challenges that China faces at this point in its economic development are far more important than whether its slowdown is a gap or a trap. What comes after the catch-up to advanced economies operating on the technological frontier? This is where China’s stated goal of shifting from imported to indigenous innovation comes in. Middle- versus high-income status is a relative comparison for developing economies seeking to operate on that frontier. Notwithstanding the temporary effects of periodic exogenous disturbances – such as deleveraging, global slowdowns, or even trade wars – catching up to the frontier and joining others pushing to move beyond it is the ultimate reward of economic development. That goal is enshrined in President Xi Jinping’s aspiration for China to achieve high-income status by 2050.

Lastly, productivity growth is far more important than GDP growth in determining a country’s development prospects. As such, I would be far more worried about China falling into a productivity trap than a GDP growth trap. A new study on total factor productivity by a team of Chinese researchers offers some comfort here. Like the work of Pritchett and Summers, this latest assessment of Chinese TFP growth reveals several discontinuities over the past 40 years. But the underlying trend for the past five years is encouraging: annual TFP growth of around 3%, with especially strong growth in the tertiary sector. So, notwithstanding the recent slowdown in aggregate GDP growth, services-led Chinese rebalancing is imparting meaningful productivity leverage to the economy as a whole.

The question now is whether China can sustain its recent TFP trajectory – a distinct possibility in light of an increasingly powerful shift to indigenous innovation and the sustained services-led productivity of a growing cohort of well-educated knowledge workers – and also reap the benefits of continued upgrading of its capital stock. If it can, the new Chinese study concludes that China’s potential GDP growth rate could hold at nearly 6% over the next five years. Such an outcome would conform quite closely with China’s longer-term ambitions.

So, yes, the days of 10% Chinese growth are over. That was inevitable. But there is good reason to believe that the real story is the shift in Chinese output from quantity to quality. That suggests that China will defy yet again widespread fears of a looming middle-income trap.

(End)