赫克歇尔-俄林模型实证研究的结果表明，各国间存在着生产要素效率的不同。请解释这将如何影响要素价格均等化这一概念。
In the discussion of empirical results on the Heckscher-Ohlin model，we noted that recent work suggests that the efficiency of factors of production seems to differ internationally．Explain how this would affect the concept of factor price equalization．