In my post, I specifically defined it relative to US population. But what you are implying is correct - in general, "over-represented" is subjective. Had I used only US population with SAT score above some threshold, the numbers would have differed.
In fact, it's past the time time to address your question, and start using the term consistently. Stanford themselves boast how "underrepresented minorities" are the fastest growing group [1], without defining the term. Presumably they mean relative to population, but somehow they don't count whites among that group, despite them being, at Stanford, both under-represented and a minority.
We would all greatly benefit if, instead of being so coy, they would openly state: "Yes, there are fewer non-Jewish whites than what would be expected from population numbers, but that is because they're just not smart enough."
After all, how can the conversation advance, if the participants are dishonest, hiding or ignoring data as is convenient?
There's literally a definition of under-represented groups in that article. What are they hiding? The whole point is that raw intelligence on some absolute scale (however measured) is not the only factor in admissions.
Their definition states which groups they consider under-represented, but not the criterion for under-representation. That this criterion is total US population (and not e.g. population with SAT score worthy of Stanford) is implied, not explicit.
The implication may be clear to you and I, but the post I replied to was literally asking what over-represented means (what, not who). Presumably they would ask the same of that Stanford article.
Dude, he is replying to a comment saying "over-represented among non-international undergraduates, relative to their US population.". I think it doesn't take a Ph.D. in linguistics to comprehend what everyone is saying here: some racial subgroup is represented at x% in total population but at y%>x% in the population under consideration.
You can disagree with it, as I do (where I don't expect every non-racial sub-population to show proportions of race corresponding to the total population) but how can you not comprehend what he's saying? Like, you don't understand it? Come on, postulate a few explanations in English for what it could possibly mean.