<p>4th floor, I don't have those numbers for other schools. What I have (had) was a set of numbers for my own, which is a large public research university. But I think what I've described generalizes to most, and probably all, research universities. </p>
<p>As I mentioned, there are multiple factors in the cost structure of different programs, including salaries, teaching loads, class size, the technology in the classroom. There is a fairly strong, basically market-driven, differential in salaries across academis disciplines. A competitive research university has to keep up with the market. Even within the social sciences, there's a fairly consistent and strong hierarchy, which goes something like this: econ, psych, polisci, soc, and anthro -- with geography being higher in the more technical fields such as remote sensing. Teaching loads, while at many universities nominally equivalent across the different departments, are in fact highly differentiated with the humanities faculty having the highest loads (courses and students enrolled per semester).</p>