Correlation is not causation– Greek life edition

I was going to post on this last week.  Then didn’t.  Then a FB friend (who is surely reading this) posted and I felt I had to offer my brief commentary on how not to interpret data like this.  From Vox:

 Researchers at Gallup believe they found a formula for a good life after college, and students in fraternities and sororities are more likely to follow it than most.

The polling firm interviewed tens of thousands of college graduates about their well-being after college. They found a few steps students can take in college that predict whether they will be thriving financially, socially, and in the workplace after they graduate. Put simply: “Find professors who excite you and make you care. Get very involved in an activity. Find a mentor. Get an internship. Work on a long-term project.”

Students who were in fraternities and sororities were more likely to do all five — and more likely to say they had a sense of purpose at work, that they had strong connections to friends and family, and that they like where they live, Gallup said this week.

Hmmm.  Alas, we don’t randomly assign people to fraternities (put me in the control group!) so this presents a classic case of selection bias.  Are people who join fraternities systematically different in personality characteristics?  Absolutely.  Might those personality characteristics also contribute to being more involved in campus life, independent of belong to a Greek organization?  Absolutely.  The Vox write-up suggests this, but not nearly strongly enough:

Still, it’s possible that the type of students who join fraternities and sororities are also more inclined to make personal connections with professors and to get involved in extracurriculars in the first place [emphasis mine], or that students at colleges with Greek life are more likely to be happy after graduation than students at colleges without, regardless of whether they pledge. Students who participate in Greek organizations are also less likely to have debt, researchers found.

The results indicate that despite the bad reputation Greek life can have for drinking, hazing, and sexual assault, the experience is a positive one for many students — and that reforms to sororities and fraternities should preserve the factors that correlate with students’ later well-being, said Brandon Busteed, executive director of Gallup Education, in a report on the findings.

Of course, there’s a way to address this.  Not perfectly, but it generally does a solid job.  It’s called additional measures and multivariate regression.  Barring any kind of statistical control, this report ultimately strikes me as pretty useless and comes down to little more than “students who choose to join intensive, voluntary campus organizations also more likely to engage with academic facets of college life.”  Now, maybe the fraternities and sororities are, in fact, causing more of this (and really, it would not surprise me if they don’t make a small contribution in this regard).  But barring better analysis, best to stick with the mantra– correlation is not causation.


About Steve Greene
Professor of Political Science at NC State

5 Responses to Correlation is not causation– Greek life edition

  1. Have I been demoted to just a FB friend?? 🙂
    Thanks for the interpretation, whether it was me or someone else who posted this article last week. I definitely read it, and while I see the difference between correlation and causation, what I got out of the article is what we’ve been trying to say for years – involvement on campus and excellence in academic performance are not mutually exclusive. Whether one causes the other matters less to me than the fact that both are important.
    And it was nice to see some positive statistics about Greek involvement for a change!

  2. PS you posting anything on your blog about Greek life is the textbook definition of “click bait” for me 🙂

  3. R. Jenrette says:

    As a group, fraternity and sorority members come to college life with lots of connection already. Then they double down on it with life long school connections. . That’s why the rich get richer.
    The best thing non-connected students can do is to work at making connections while at college.
    Join those interest groups and get active in extracurricular activities. It’s all about networking.
    Wish I had known that way back then.

  4. Hello R – that is definitely true for many members. I’ve also worked with hundreds of students who came to the university not so well connected, but found their niche and grew their network as a fraternity or sorority member. Many of them were on the shy or awkward side, and being part of something larger than themselves, that they could contribute to, made all the difference in their undergraduate and post-graduate life.

    Greek life is not the only way to do this, of course. Having attended an institution without a Greek community, I found that connection and network through band. The difference is the national network available through a Greek organization, which is much more broad than an organization based solely at one institution.

    • R. Jenrette says:

      Hey, Jeff. There are some campus interest groups and clubs that have national reach, like Young Democrats and Young Republicans. In a state university especially, it’s a good way to connect with the future movers and shakers in your state.

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