Features of the model
Relative endowments of the factors of production (land, labor, and capital) determine a country's comparative advantage. Countries have comparative advantages in those goods for which the required factors of production are relatively abundant locally. This is because the profitability of goods is determined by input costs. Goods that require inputs that are locally abundant will be cheaper to produce than those goods that require inputs that are locally scarce.
The original, 2x2x2 model was derived with restrictive assumptions, partly for the sake of mathematical simplicity. Some of these have been relaxed for the sake of development. These assumptions and developments are listed here.
Both countries have identical production technology
This assumption means that producing the same output of either commodity could be done with the same level of capital and labour in either country. Actually, it would be inefficient to use the same balance in either country (because of the relative availability of either input factor) but, in principle this would be possible. Another way of saying this is that the per-capita productivity is the same in both countries in the same technology with identical amounts of capital.
Production output is assumed to exhibit constant returns to scale
In a simple model, both countries produces two commodities. Each commodities in turn is made using two factors of