We write a lot on Economix about whether college is worth it. In a piece in Investor’s Business Daily, Alex Tabarrok, an economics professor at George Mason University, suggests that Americans are focusing on the wrong question. They shouldn’t be debating whether college in general is “worth it”; they should instead be thinking about whether the specific college degree they’re considering is marketable.

A smaller share of students are choosing majors that are in demand, he writes:

Over the past 25 years the total number of students in college has increased by about 50 percent. But the number of students graduating with degrees in science, technology, engineering and math (the so-called STEM fields) has been flat… If students aren’t studying science, technology, engineering and math, what are they studying? In 2009 the United States graduated 89,140 students in the visual and performing arts, more than in computer science, math and chemical engineering combined and more than double the number of visual and performing arts graduates in 1985.

Dr. Tabarrok notes STEM majors are more likely to find work and also to find high-paying work. Then he emphasizes that the choice of concentration not only matters for a worker’s earnings but for the entire economy. His conclusion:

Economic growth is not a magic totem to which all else must bow, but it is one of the main reasons we subsidize higher education. The potential wage gains for college graduates go to the graduates — that’s reason enough for students to pursue a college education. We add subsidies to the mix, however, because we believe education has positive spillover benefits that flow to society. One of the biggest of these benefits is the increase in innovation that highly educated workers bring to the economy. As a result, an argument can be made for subsidizing students in fields with potentially large spillovers, such as microbiology, chemical engineering, nuclear physics and computer science. There is little justification for subsidizing majors in the visual arts, psychology and journalism.

What do you think of this argument, readers? How would you measure the gains — economic or otherwise — that come from different college majors?