college graduationrobb3d via flickr
Legacy admissions — giving children of alumni preference in the admissions process — has a long history in American higher education. Kids often follow their parents to the same school, frequently applying with the hope that they'll get a favorable look.

How much of a boost do they get? A 2011 study of 30 elite institutions found that the children of undergraduate alumni ("primary legacies") were, on average, 45.1% more likely to get in.

An earlier study by Princeton's Thomas Espenshade found that the legacy advantage was equivalent to a 160-point swing on an SAT score.

That's not a tiebreaker between equally qualified applicants; it's a massive advantage. That's particularly clear at the Ivies:

Keep in mind, those legacy admissions rates are self-reported.

Selective public universities, including the University of Michigan and the University of Virginia favor legacies as well.

There's some evidence that the practice has declined. The proportion of legacy admissions is lower than it used to be. In 1958, the legacy admissions rate was 70%. A pamphlet from the Princeton Alumni Council reads:

"No matter how many other boys apply, the Princeton son is judged from an academic standpoint solely on this one question: Can he be expected to graduate? If so, he's admitted. If not, he's not admitted. It's as simple as that."

Moving beyond that is a good thing, but we still a long way to go to create an fair and equal system.

Legacy applicants tend to be white and wealthy. Legacy admissions therefore contribute to the rich kid problem at elite schools. Underrepresented minorities make up about 12.5% of the applicant pool at selective schools. They make up only 6.7% of the legacy pool.

So why do schools do it?

The answer, despite what they might say about tradition and close alumni relationships, is clearly about money. An alum who encourages their child to apply to their alma mater likely had a good experience, and if their child gets into the school, they're even more likely to donate. Wealthy families or heavy donors are likely to get additional preference.

Some top schools, however, have shown that you can survive in a purely meritocratic system.

It's worked out pretty well for CalTech and MIT, neither of which considers legacy in admissions decisions.

MIT Admissions Counselor Chris Peterson puts it pretty bluntly in a blog post:

"I personally would not work for a college which had legacy admission because I am not interested in simply reproducing a multi generational lineage of educated elite. And if anyone in our office ever advocated for a mediocre applicant on the basis of their "excellent pedigree" they would be kicked out of the committee room."