Vertical specialialization in world trade


The Economist reminds us of a common notion, but not explored a lot in the news. Decline in demand overall, and finance, is a major concern for trade partners, but is complicated because products often travel from country to country in stages of completion to finished product.

Economists believe that an additional reason for these sharp and co-ordinated drops lies in a fundamental change in the nature of global trade over the past three decades, as a result of the rise of global supply chains. When David Ricardo posited that comparative advantage was the basis of trade, he conceived of countries specialising in products, such as wine or cloth. Now, they specialise not so much in final products as in a step, or steps, in the production process, what economists call “vertical specialisation”. Vertical specialisation has grown by about 30% and accounts for a third of the growth in trade over the past 20 to 30 years.

Vertical specialisation led trade to grow much faster than it would have otherwise. Earlier, a tractor made in America would use American steel and parts: its only contribution to trade would come if the finished item were exported. Now, that tractor may use steel from India that is stamped and pressed in Mexico, before being exported to Tanzania. Global supply chains have increased the amount of international trade involved in getting a product made and delivered to its final user.

On the flip side, declines in demand that would once have resulted primarily in a fall in domestic output, and would only have had a second-order effect on other countries’ exports because of the decline in domestic incomes, now immediately affect trade flows in several countries. The same mechanism that was responsible for the remarkably rapid growth in trade since the early 1980s is now amplifying the extent to which trade responds to a decline in demand, which explains the remarkable synchronisation with which trade is declining everywhere.

Kiplinger offers an example of such a process, the manufacture of plastic pipe. Product crosses the border multiple times as it is completed.

Update: Voxeu covers the issue, of course, very thoroughly.

Much of U.S.-Canadian trade involves goods crossing the border multiple times before the products in which they’re used are finally completed. Indeed, supply chain integration has long been one of the main benefits of NAFTA, given its role in increasing trade and lowering production costs. Makers of water and wastewater equipment, the manufacturers hit hardest by the stimulus bill’s Buy American rules, accounted for $10 billion in cross-border trade last year. Other industries with North American supply chains will get dragged down, too, if they’re unable to buy from Canada and Mexico.

Consider the case of IPEX, a Canadian-based manufacturer of thermoplastic pipe systems for the construction sector, to see how the problem is playing out on both sides of the U.S.-Canadian border. Before it can participate in a U.S. construction project, IPEX is now asked to sign a certificate affirming that all its products are made in the U.S. Since IPEX’s supply chain is integrated across the border, its product load is invariably a mix of Canadian and U.S. parts. The result is that it is either unable to bid on the project or the parts are turned away if they have already been shipped to a construction site.

“Before Feb. 17, we had access to the U.S. market,” says Veso Sobot, an IPEX engineer, referring to the date the stimulus bill became law. “Since Feb. 17, we have not.” That’s bad news for companies such as Westlake Chemicals. Westlake, based in Houston, manufactures the raw materials IPEX uses to make its pipes. IPEX’s troubles in the U.S. market will force it to cut back production.

“America ships way more product into Canada than Canada ships into America,” says Sobot. “If we injure either one of us, we’re injuring ourselves collectively, and we won’t be able to compete effectively on the world stage.”