Can you explain what exactly you think is "bias"?
If an institution accepts a higher percentage of Asians than the percentage in the US population (or amongst the applicants, or the amongst the qualified applicants?), is that a bias that needs to be corrected?
If an institution accepts a lower percentage of males than the percentage in the US population, is that a bias that needs to be corrected?
If an institution accepts a higher percentage of Alumni relatives?
If an institution accepts a lower percentage of people with Down syndrome?
If an institution accepts a higher percentage of people who were interested in a particular subject in high school?
What about correlation and causation amongst the above, as in one gender being more involved in one particular subject, or parents from one race being more likely to steer their progeny towards a particular subject?
There are no easy ways to account for all the obstacles a person encounters before he applies for college. Low income families, broken households, abusive parents, devastating medical conditions, high crime neighborhood, toxic cultural environment, etc, etc, etc...
I know for a fact that some of the people in charge of admission cannot even agree on what the end goal is. Equal chance of success independent on the student's qualifications? Equal chance of success independent of the student's skill in choosing the right family to be born in?
People in the US love to pretend that they are using affirmative action to mitigate the effects of their racist society. Somehow, when you give a middle class, black kid from a two parent family an advantage over a low income, single mother Asian kid, you are striking a blow for social justice... But suggest that Alumni do not get an advantage, and that income is never taken into account during admission (the best schools already do the latter) and you are dirty Commie.