Which factor is the most important in the direction of immigration?
Of course, living houses are important in the direction of immigration.
Because the inside&outside (clothes + foods + travels + money) are similar, but living houses require at least two houses{the house in American + the house in out of American + ...}.
So it is only one way that help cheaper houses in the direction of immigration.

If you are one traveller, you don't need change anythings.
If you are one immigrater, you may order one house in American so that you can protect your American situation.
Just houses have {the house in American + the house in out of American + ...}.
It isn't clear {inside American or outside American} of (clothes + foods + travels + money).
It is very clear {inside American or outside American} of houses.