Drinking in college? Yep, it hurts your GPA

When those in authority try to get college students to drink less, they typically go for scare tactics. They remind students about the dangers of alcohol poisoning, arrest, or accidents. Because binge drinking can be so hazardous, over 100 college presidents have signed on to a movement called the Amethyst Initiative that seeks to reduce bouts of heavy drinking. (And believe it or not, the main policy recommendation of this group is to lower the drinking age!)

So students have heard about the most extreme (and low-frequency) negative effects of alcohol consumption on campus. But what about more frequent outcomes? There’s one concern common to all college students: academic performance. There aren’t many people like the Delta frat brothers in the movie Animal House, who are proud when Dean Wormer tells them: “Here are your grade point averages. Mr. Kroger: two C’s, two D’s and an F. That’s a 1.2. Congratulations, Kroger. You’re at the top of the Delta pledge class.”

But it’s tricky to test the effects of alcohol consumption on academic performance. One big problem is that there may be another variable explaining both poor student performance and drinking (for example, mental health issues) so the connection could be what scientists call “spurious” (seemingly correlated, but there’s something in the background that promotes both behaviors).

I love to report on a truly clever research design, and that’s what we have from economists Scott Carrell of UC-Davis and his colleagues Mark Hoekstra and James West. Their article published by the National Bureau of Economic Research takes advantage of a unique data set, allowing them to test the effects of starting to drink more heavily.

Their data come from the 2000-2006 classes of the United States Air Force Academy (USAFA). Unlike most college campuses, the ban on underage drinking is strictly enforced and can lead to expulsion. Surveys show that drinking before age 21 is much lower at the USAFA than at most college campuses. Another advantage: The USAFA has a highly standardized curriculum where students don’t choose their subjects or professors in core courses and everyone takes the same exams.

So hand it to the researchers for finding an ideal research setting to answer their question (there ought to be a prize for this)!

Now if you’ve followed me this far, using these data, what would be the ideal test of the effects of alcohol? You’ve got it: Each cadet’s 21^st birthday. Prior research clearly shows a sudden increase in drinking immediately following turning 21. So they were able to look at students who turned 21 shortly before final exams versus those who turned 21 afterwards.

The results: Drinking definitely affects academic performance. In an interview, Scott Carrell notes that the reduction is approximately half a letter grade. And the effect is strongest for high-performing students. The trend doesn’t just last for the week of the birthday party, but continues for around eight months afterward.

So college binge drinking doesn’t just lead to low-frequency, high-impact outcomes like fatalities. It can also lower GPA and, the authors’ suggest, future life chances as a result.