21 Krugman/Obstfeld/Melitz • International Economics: Theory & Policy, Ninth Edition
After presenting the basic theory behind the Heckscher-Ohlin theory, the rest of the chapter examines empirical
tests of the model, beginning with a case study looking at income inequality in the United States Wages paid
to skilled workers in the United States have been rising at a much faster rate than those paid to unskilled
workers over the past few decades. At the same time, there has been a large increase in international trade.
Given that the United States is relatively abundant in skilled labor, the Heckscher-Ohlin theory would
predict that increased trade should lead to higher wages for skilled workers and lower wages for unskilled
workers. On the surface, this appears to be an empirical confirmation of the theory. However, other studies
argue that rising wage inequality can only partially be explained by increased trade. According to the
Heckscher-Ohlin model, the increase in skilled wages should be driven by an increase in the price of skill
intensive goods following trade. However, skill intensive goods prices have not increased by nearly the
same proportion as skilled wages. If rising wage inequality in a rich country like the United States is
driven by factor price equalization, then we should also observe a narrowing gap in developing countries
that are exporting low-skill intensive goods. However, income inequality in these nations is actually larger
than in rich countries. Finally, trade between rich and poor nations is simply not large enough to be entirely
responsible for the size of the income gap. Rather, the increasing skill premium is most likely due to
skill-biased technical innovations like computers that have increased the productivities of skilled workers
more than unskilled workers.
Another empirical observation testing validity of the Heckscher-Ohlin theory is the Leontief paradox. This
is the observation that the capital intensity of U.S. exports is actually lower than that of U.S. imports, exactly
the opposite of what the theory would predict for a capital abundant country. Further evidence of this paradox
is found in global data, with a country’s factor abundance doing a relatively poor job of predicting its trade
patterns. Finally, the theory predicts a much larger volume of trade (given observed differences in factor
endowments) than we actually see in the data. A country like China, for example, has a significant abundance
in labor. However, China’s net exports of labor-intensive goods are lower than what the theory would predict.
Similarly, U.S. net imports of labor-intensive goods are lower than what would be expected given its relative
labor scarcity. An explanation for this “missing trade” is that the assumption of identical technology across
countries is flawed. Rather, there are significant differences in productivity across countries. That said, when
the sample is restricted to trade between developed and developing countries (i.e., North–South trade), the
Heckscher-Ohlin theory fits well (e.g., the United States imports more low-skill products from Bangladesh
and more high-skill products from Germany). This observation has motivated many economists to consider
motives for trade between nations that are not exclusively based on differences across countries. These
concepts will be explored in later chapters. Despite these shortcomings, important and relevant results
concerning income distribution are obtained from the Heckscher-Ohlin theory.
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