誰搶走了你的工作:機器人還是全球化

In the first part of this mini-series, I surveyed how robots, automation and other productivity-enhancing technology is affecting industries at the heart of the economy as well as some more exotic science fiction examples. In the second part, I considered the “Solow paradox” — the strange combination of breathless innovation with stagnant labour productivity (though not so strange when you realise there is not that much investment in capital embodying the new technologies).
在這幾篇迷你係列文章的第一部分，我調查了現今機器人、自動化以及其他提高生產率的技術是如何影響經濟核心產業以及一些更奇特的科幻小說例子。在第二部分，我考察了“索洛悖論”(Solow paradox)——令人喘不過氣的創新與停滯不前的勞動生產率的奇怪組合（不過當你意識到並沒有那麼多體現新技術的投資時，這就沒那麼奇怪了）。

Today, we focus on the question of greatest political consequence. Who stole the jobs — was it robots or foreigners? Or less tendentiously, was the falling number of manufacturing jobs in rich countries caused by trade liberalisation or by automation and other productivity-enhancing technological change?
現在，我們把重點放在這帶來的最大的政治影響上。誰偷走了工作——是機器人還是外國人？或者不那麼帶有傾向性地來看，富裕國家制造業就業數量不斷下滑，是由貿易自由化或自動化和其他提高生產率的技術變革造成的嗎？

For it is largely manufacturing jobs we are talking about. The US is special in that overall employment rates (for all jobs taken together) have fallen since the turn of the century, and for longer than that among men. As Jason Furman and his colleagues have documented extensively, the US faces an especially aggravating version of a more common problem in which manufacturing jobs have not only disappeared but failed to be replaced by anything at all.
我們主要討論製造業就業。美國的特殊之處在於，自從進入21世紀以來，總體就業率（所有工作都算在一起）一直下滑，並且下滑時間長於男性就業率下滑的時間。正如傑森?福爾曼(Jason Furman)及其同事記錄的大量文檔所表明的那樣，美國正面臨着一個比較普遍的問題的嚴重版——製造業崗位不僅消失了，而且沒有得到任何替代。

So are robots or trade to blame? The simple and largely true answer is: both. But there is still a question of their relative importance, and of what exactly the blame entails.
那麼到底該怪機器人還是貿易？一個簡單而大致上正確的回答是：兩者都怪。但現在還存在另一個問題——兩者相對的重要性、以及它們到底罪在哪裏。

All industrialised countries have been shedding labour in manufacturing for decades, a process that started before the wave of globalisation in the 1990s. It is clear that the balance of trade has little to do with it: the similarities between structural change in employment in perennial-surplus Germany and permanent-deficit US are much greater than the differences.
數十年來，所有工業化國家的製造業都在減員，該過程始於上世紀90年代全球化浪潮開始前。貿易差額明顯與該問題無關：常年處於貿易順差的德國與始終處於貿易逆差的美國，在就業結構變化方面的相似點遠遠超過差異。

But the growth in overall trade that accompanied the regional and global trade liberalisation during the three decades before the global financial crisis will have the effect of changing the employment and production structure of the opening economies — indeed that is part of the point of lowering trade barriers. Standard theory predicts that with more open trade, countries will specialise more intensively in production that makes most use of their relative endowment of labour, skill, capital and natural resources.
但全球金融危機發生前的30年裏的區域和全球貿易自由化帶來的總體貿易增長，將會改變開放型經濟體的就業和生產結構——實際上這正是減少貿易壁壘的部分意義。標準理論預測，隨着進一步開放貿易，各國將更集中地專攻最大化地利用它們在勞動力、技能、資本和自然資源上的相對稟賦的生產。

Recent research by Adrian Wood measures to what extent this has indeed happened. As the table below shows (for more detail, look up the background paper) the share of manufacturing in global production and employment fell noticeably in the three decades from 1985. But different regions went through dramatically different changes. In particular, in most land-scarce regions (particularly prone to specialise in manufacturing, according to theory) the share of manufacturing in the economy expanded, while it shrank in all land-abundant ones.
艾德里安?伍德(Adrian Wood)最近的研究衡量了這種情況發生的程度。如下表所示（若需要更多細節，請查閱相關論文），在1985年之後的30年裏，製造業在全球生產和就業中所佔比例明顯下滑。但不同地區經歷了截然不同的變化。尤其是，在大多數土地稀缺的地區（根據理論，這些是尤其傾向於專攻製造業的地區），製造業在經濟中的佔比有所擴大，而在所有土地充裕的地區，製造業在經濟中的佔比縮小了。

Wood suggests this shows that the dramatic changes in manufacturing employment can be laid at the door of economic globalisation. But the story is not as simple as that. Look where the biggest changes in employment shares happened. Among rich countries (OECD members), the manufacturing employment share fell just as much in land-rich and land-scarce economies. The output share increased in land-scarce ones — but in conjunction with the loss of manufacturing jobs, this is surely an effect of automation and technology. Meanwhile the two other regions with particularly large structural changes were the Soviet sphere, which in 1985 had an overgrown and inefficient manufacturing sector that collapsed under its own weight once the economy was liberalised, and China, whose liberalisation and trade integration surely contributed to its industrial revolution.
伍德認爲，這表明製造業就業的急劇變化可以歸咎於經濟全球化。但事實沒那麼簡單。看看哪些地區的製造業就業佔比變化最大。在富裕國家中（經合組織(OECD)成員國），土地充裕經濟體與土地稀缺經濟體的製造業就業佔比降幅相當。製造業在土地稀缺經濟體的產出中的佔比增加——但同時製造業就業流失，這肯定是自動化和技術的影響。與此同時，另外兩個結構變化特別大的地區是前蘇聯地區和中國。前者在1985年製造業發展過快、效率低下，在經濟進行自由化時被自身重量壓垮，而後者的自由化和貿易一體化顯然促進了工業變革。

What all this points to, then, is a process in which many poor countries went from a pre-industrial employment structure to an industrial one (but some stagnated, in particular in Africa), and in which all rich countries largely went from an industrial to a service-based employment structure. The poor country transition or lack of it no doubt owes a lot to the ability to enter the world trading system. In the rich country transition this looks more like what you would expect from the continued growth in manufacturing productivity, echoing what had earlier happened in agriculture.
那麼，這一切都指向了很多貧窮國家從工業化前就業結構到工業化就業結構的過程（但有些國家的這一過程陷入了停滯，特別是在非洲），以及所有富裕國家基本上從工業化就業結構到以服務業爲基礎的就業結構的過程。貧窮國家實現轉型或未能轉型，無疑與它們進入世界貿易體系的能力有很大關係。而富裕國家的轉型，看起來更像是製造業生產率持續增長所必然帶來的，與之前農業出現的情況相似。

And conversely, there is direct evidence for the automation thesis. A new study by Daron Acemoglu and Pascual Restrepo tries to measure the effect on US jobs (and wages) of the increased use of industrial robots. An interview with Acemoglu about the findings puts the number of manufacturing jobs lost because of robots at 670,000 between 1990 and 2007.
相反，有直接證據支撐了自動化造成製造業失業的論點。達龍?阿西莫格魯(Daron Acemoglu)和帕斯夸爾?雷斯特雷波(Pascual Restrepo)的新研究試圖衡量，加大使用工業機器人對美國就業（和工資水平）的影響。在一篇就研究發現對阿西莫格魯的採訪中，1990年至2007年因機器人而造成的製造業失業數字爲67萬。

What lessons can we draw? First, that both trade and automation play a role. But second and more importantly, that the two cannot be neatly separated — automation-driven productivity growth and attendant job loss may be both an ultimately unavoidable part of economic change and be accelerated by trade liberalisation. Rich economies with highly-skilled labour forces are well placed to respond to greater trade by specialising in higher-value added products — just those where automation can do the most to increase productivity. Hence, for example, the success so far of the US car industry, which produces more vehicles than ever and exports finished cars to China.
我們能得出什麼結論呢？首先，貿易和自動化都發揮了作用。但第二點也是更爲重要的一點是，二者無法徹底分開，由自動化驅動的生產率增長以及隨之而來的就業流失可能都是經濟變革最終不可避免的一部分，並且被貿易自由化加速。擁有高技能勞動力的富裕經濟體有能力通過專門生產更高附加值的產品，應對貿易擴大——在更高附加值產品領域，自動化最能提高生產率。例如迄今美國汽車業的成功，其生產的汽車數量超過任何時候，並將整車出口到中國。

But third, that a protectionist trade policy may not do much good even if trade was part of what eroded certain jobs in the past. For if trade helped automation along the way, it is not as if restricting it will wind automation back. At most it may delay further automation, but that will come at a cost. In particular, it will make it harder to export manufacturing goods into a global market that uses the most cost-effective techniques. Trade sceptics who aim to protect manufacturing jobs should be alert to the distinction of protectionism and mercantilism. While the latter aims to boost exports, the former, by restricting imports, may well hold back exports, too.
但第三，儘管貿易曾經造成過去某些就業的消失，但保護主義貿易政策可能也不會有大好處。因爲，即使貿易曾經在這個過程中幫助過自動化，限制貿易也不會讓自動化倒退。它充其量可能會推遲進一步自動化，但這是要付出代價的。特別的，它將加大把製造業產品出口到利用最節約成本技術的全球市場的難度。試圖保護製造業就業的貿易懷疑論者應注意保護主義和重商主義的區別。後者旨在擴大出口，而前者由於限制進口很有可能同樣阻礙出口。