If they’re smart and have potential to succeed, a meritocratic measure should rank them favourably. The problems with tipping the scales too far are (1) it’s inefficient, in that the total likely production of the student body is lowered and (2) it can backfire, by visibly creating a two-tier student body between those admitted on their own merits and those admitted for other reasons.
In the United States, we tend to tip the scale towards privilege through legacy admissions and institutional advancement programs. We also tip them towards social goals through affirmative action.
Based on my non-statistical observational view, these programs are insanely effective at helping these students. Hell, some of the best students in the uni are exactly these poor students. The most successful student from my batch grew up in a village in the middle of nowhere and went to MIT for a physics PhD.
I have seen very little evidence of two-tier because some of the privileged are lazy and don't achieve much in uni.
We have to this point been unable to produce such a measure, despite more than a century of trying.
We have not been able to produce a precise measure. But we’re able to e.g. identify quartiles. Compressing the measure to “likely to graduate” tends to take care of a lot of the lifting.
That’s why a random selection component makes sense. It is honest about our limitations. And it removes the stigma from those who met the fuzzy threshold but didn’t get admitted.