Everybody gets ethnicity wrong. There's no such thing. It, like many other things, is culturally determined-- but (and this is a big but) it is almost always

Everybody gets ethnicity wrong. There's no such thing. It, like many other things, is culturally determined-- but (and this is a big but) it is almost always contentious between cultures, and often within cultures. Not only is there no good universal set of ethnic labels that will satisfy everybody, there's likely no set of local labels that will satisfy everybody in a given area. I can't think of too many good reasons to attempt to collect "ethnicity" in a web form, but if I were going to, I'd make it a text field, and let people enter whatever the hell they want to.