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Intl TradeEconomies of scale and intra-industry trade

Formulas for this chapter

Average cost per unit

Average cost = total input required / quantity produced

To show economies of scale numerically. Compute it at two output levels; a falling figure is economies of scale, a rising one is diseconomies.

Total input
Labour or cost required at that output, often a fixed part plus a variable part
Quantity
Units produced in the period

Labour saving from concentrating production

Saving = (labour for each country separately, summed) - (labour for one country producing the whole output)

The class's demonstration that identical countries gain from trade. With labour = fixed + quantity, the saving equals the fixed requirement that is eliminated.

Fixed requirement
The part of labour that does not vary with output, 5 in the class table

Intra-industry trade index

T = 1 - |X - M| / (X + M)

To measure how much of a country's trade in an industry is two-way. T = 0 means one-way trade only; T = 1 means exports equal imports. State the level of industry aggregation, because widening it raises T.

X
Value of exports of that industry or commodity group
M
Value of imports of the same group
Step 2 of 28
The real wordsTheory

Which assumptions break the model

The deck opens with a careful distinction that is worth a mark on its own.

  • Relaxing most assumptions of Heckscher-Ohlin modifies but does not invalidate the theory
  • Relaxing perfect competition and constant returns to scale requires complementary theories to explain trade
  • Additional models are also needed for trade based on differences in technological change over time

So this chapter and the next are not corrections to Heckscher-Ohlin. They are additions alongside it.