In a new study by Duke economist Peter Arcidiacono (http://public.econ.duke.edu/~psarcidi/aa.pdf), the author finds that among the UCs, Berkeley seems to favor URMs the most in admission decisions. In other words, white applicants (the author didn’t show data on asians) have the most disadvantage as compare to URMs in admissions to Berkeley. The author has an interesting graph in the paper, which shows that the academic index distribution of URM admits has a lower mean than that for the white rejects, while the white admits have a mean of more than one standard deviation higher than that for the URMs. The author did some further comparisons for other UCs and found that Berkeley seems to the the one campus that seems to favor the URMs the most.
A previous study by the same author on affirmative action by Duke University admissions generated considerable controversies on the Duke campus, which resulted in angry URM students surrounding the economics department and demanding the retraction of the paper by the professor.