The Gap between Interdisciplinary Teaching and Interdisciplinary Research and Its Consequences on the Earnings Inequality across American Universities

Interdisciplinarity is highly advocated in higher education today. However, empirical evidence on the benefits of interdisciplinarity is restricted to learning outcomes during college rather than post-graduation outcomes. Some even argue that it has no positive effect on earnings returns because it does not solve practical problems in the labor market. We question this argument by clarifying two different mechanisms through which interdisciplinarity benefits students. Students could gain better knowledge and skills through interdisciplinary teaching (IDT) and improve their earnings returns in the labor market. Or, they could benefit from attending schools that primarily pursue interdisciplinary research (IDR) - such schools tend to have higher institutional prestige, which confer students higher economic returns to their degrees without necessarily or directly increasing their practical skills. Assisted by natural language processing techniques, we use two big textual databases to quantitatively measure IDT and IDR in the same methodological framework. We then look at how the two types of interdisciplinarity matter for economic returns to college degrees. We find that the level of our numeric indices for IDT and IDR may not always align at the same institution; IDT has a larger earnings premium for students’ future earnings than IDR does; earnings returns to IDT are higher for institutions with larger enrollment sizes where the current IDT is low. These findings suggest a horizontal stratification based on IDT and IDR, highlighting the risks for institutions with a gap between the levels of interdisciplinary research and interdisciplinary teaching.