From a research perspective it is more adequate to talk about “cross-cultural” instead of “international” research.

The latter term is misleading as one immediately starts to think in categories of states, nationalities and borders. But in fact “cross-cultural” research often is necessary within a single country (e.g. cultural sub-populations in Belgium, Switzerland or Canada or ethnic-minorities in the USA), showing that the real boarders are cultural, not national ones and that “cross-national” is not equivalent to “cross-cultural”.

(Wulf Schlund & Dirk Frank, p&a Market research 2005, S. 16-20)