A new IZA discussion paper by Steven Hemelt, Kevin Stange, Fernando Furquim, Andew Simon, and John Sawyer provides the most comprehensive overview of the costs associated with teaching across 20 fields based on a large and diverse sample of four-year colleges and universities from the Delaware Cost Study. The results show that the cost of a unit of instruction differs markedly by discipline.
A student credit hour of electrical engineering, for example, costs twice as much as a credit hour of English. At the other extreme, math is about 22 percent cheaper per credit hour than English. In general, pre-professional fields like business and accounting, along with fields that typically command higher earnings like engineering and nursing, are more costly to teach than the social sciences and humanities.
What explains this variation in costs across fields?
The authors partition differences in instructional costs into four drivers: faculty salaries, faculty workload, class sizes, and non-salary expenses (e.g., lab and equipment costs). Differences in class sizes and faculty salaries tend to explain the bulk of differences in costs across fields. For example, though average salaries are higher for economics faculty than English faculty, class sizes in economics are substantially larger than in English, resulting in costs of instruction per credit hour that are slightly lower in economics than English. Business and accounting faculty also earn more relative to English, but the larger class sizes in these fields only partially offset those differences in pay. Faculty workload and non-personnel expenses generally play minor roles in explaining cost differences across fields.