According to the book Affirmative Action for the Rich published by Century Foundation, alumni preferences provide an admissions advantage to the children of alumni.

The book has shown that being the child of an alumnus adds the equivalent of 160 SAT points to one's application and increases one's chances of admission by almost 20 percentage points.

The book made Princeton University as an example, in 2009, the percentage of the alumni children enrolled in the university was 41.7,4.5 times the non-alumni counterpart. However, the ratio was only 2.8 times in 1992.

The book also found that the phenomenon is not only popular in the top universities, but also in religious universities.

Richard D. Kahlenberg, the author of the book, said: "an alumni preference is worth 160 SAT points. And as noted above, if two students score exactly the same on the SAT, the one without alumni parents might have a 30 percent chance of getting in, but the student with a legacy, and the same scores, has a 50 percent chance of getting in."

Triton Burg, former president of George Washington University, expressed that the university assesses every applicant comprehensively because of the complex of admission procedure, and alumni status is not the only consideration.

By contrast, at the California Institute of Technology, which has no legacy preferences, only 1.5 percent of students are the children of alumni.

In the well-known University of Notre Dame in Indiana, for example, about a quarter students belong to children of alumni.