Princeton mom Susan A. Patton’s recent letter recommending young women find husbands before they graduate certainly sparked serious discussion on the internet.

However, it looks like her opinion is backed-up with hard data.  In the Boston Glober, Kevin Hartnett discusses a study  that shows most people marry others with similar educational backgrounds.

It’s often noted that most marriages these days are between people with similar educational backgrounds: College graduates marry college graduates; high school dropouts marry high school dropouts. Sociologists call this type of sorting “endogamy”- the practice of marrying people who are like you- and they argue that this trend has the effect of reinforcing inequality in America by segregating the haves and have-nots into distinct communities that don’t mix.

Earlier this month on his blog Family Unequal, University of Maryland sociologist Philip Cohen published two charts that neatly summarize the state of marriage and education for people who tied the knot in 2011. Cohen created separate charts, which are based on the 2011 American Community Survey, for men and women because women are slightly more likely to marry down the educational ladder than men (in part because women earn more college degrees than men). As you’ll see, the segregating trend is true broadly, with 71 percent of college graduates marrying other college graduates. It is also true on a more fine-grained level: 48 percent of women who drop out of high school marry another high school dropout; 25 percent of women with a PhD marry another PhD.

These marriage groupings likely owe as much to who we hang out with as to strong personal biases against inter-educational mixing: Doctoral students study alongside each other for years, and high school dropouts probably spend a lot of the time they’re not in school with other people who made the same choices.