see: Leontif paradox - Economics department, Iowa State University. "The Heckscher-Ohlin theory states that each country exports the commodity which uses its abundant factor intensively. The HO theory was generally accepted on the basis of casual empiricism. Moreover, there wasn't any technique to test the HO theory until the input-output analysis was invented.
What: The first serious attempt to test the theory was made by Professor Wassily W. Leontief in 1954.
Result: Leontief reached a paradoxical conclusion that the US—the most capital abundant country in the world by any criterion—exported labor-intensive commodities and imported capital- intensive commodities. This result has come to be known as the Leontief Paradox. Leontief took the profession by surprise and stimulated an enormous amount of empirical and theoretical research on the subject." Source: Prof. Kwan Choi International Economics