Q. Why is it that North-South trade in manufactures look to be consistent with the results or expectations generated by the factor-proportions theory of international trade, whereas North-North trade is not?

Answer: There is a clear dissimilarity in relative factor availabilities between North and South countries no matter how we measure and define the factors of production. Thus, the factor-proportions theory of trade may possibly be sensibly expected to explain the pattern though not the volume of trade between these two groups of countries. Though the North trade partners don't differ significantly in their relative factor availabilities, thus that other forces such as scale economies play a relatively large role in determining trade patterns.