# change the drinking age using OR

Underage college students drink. A lot. OR may be able to help.

Ben Fitzpatrick at Loyola Marymount University gave a talk here on Friday about modeling college student drinking habits using mathematical tools. It was entitled “Ecological Systems Modeling of College Drinking,” and it was one of the most engaging talks I have seen in awhile.

Forty-two percent of college students confess to binge drinking, which correlates highly with several forms of violence. Individual interventions are not very successful at curbing drinking problems, but community policies on the aggregate level show promise. Can mathematical modeling be used to predict whether changing the drinking age is a good idea? The premise is that college campuses are relatively homogenous (compared to metropolitan areas), so the resulting model may be useful for policy-making.

Fitzpatrick applied statistical models, dynamical systems, and differential equations that compartmentalized the college population into several groups. His approach uses the fact that people overestimate how frequently their peers engage in risky behaviors (e.g., smoking, drinking). The higher this misperception, the more likely students are to engage in binge drinking. The Social Norms Marketing Research Project provided him with four years of data from 32 schools to estimate misperception. Linear regression was used to estimate some of the parameters needed for Fitzpatrick’s model, and it worked fairly well (R^2 > 0.99 for several parameters).

One model incorporated social interactions (e.g., peer pressure) and social norms/perceptions using a network model (similar to the SIR model used by epidemiologists) to estimate how social interactions could increase or decrease drinking problems. His simulations showed that as drinking misperceptions grow, more students engage in binge drinking (called heavy episodic drinking). I found this particularly interesting, since VCU is always distributing anti-drinking propaganda in the bathrooms (called the Stall Seat Journal, I kid you not), which in essence attempts to reduce misperceptions. Apparently, this is a good strategy for battling underage drinking.

When the drinking age goes down, the “wetness” level in campus goes up, since there are more legal ways to get alcohol. But the Amethyst hypothesis is that misperception goes down when the drinking level goes down (and wetness goes up), since it is easier to directly observe peer drinking activities. Fitzpatrick’s model suggests that results are more sensitive to alcohol availability than to misperception.

This seems to be an important first step in the debate about the drinking age. Before I commit to a policy position, I’d like to see more of these mathematical models to predict what would happen if the drinking age changed. Interestingly, research shows that binge drinking almost completely disappears after college. Maybe we should be trying to get students to finish their degrees in 4 years or less, rather than allowing them to take five or six years to finish?

John McCardle (of the Amethyst initiative and President Emeritus of Middlebury U) appeared on the Colbert Report (3/19/09) to talk about why the current drinking age of 21 is not working.

#### One response to “change the drinking age using OR”

• Jim Orlin

OR modeling of drinking behavior is a great idea!
On the surface, it is unreasonable to prohibit 18 year olds from drinking. They are old enough to vote, to serve in the military, and to marry and raise families. It’s not reasonable to forbid them from being served a drink in a restaurant or bar. For the prohibition of liquor sales to make any sense, we should have strong evidence that the prohibition is doing a lot of social good, and saving lots of lives.
Preliminary evidence seems to suggest that having a drinking age of 21 is making matters worse in terms of alcohol abuse for those under 21. It’s worth investigating further.
I am not a libertarian and believe that government can restrict some individual freedoms, but only if there are compelling arguments supported by evidence. It’s time to gather and analyze the evidence.