While there appears to be quite a lot of problems with the approach taken here, which I'll get to shortly, I must say that the concept of calculating individual value added is a good one. This is something every person should do when engaged in work for others: ask "what is my value-added here?" For professors, this is something that revolves around the primary tasks of teaching and research, along with "service."
Value added for teaching, for me, means this: whatever the students could get from reading/working on their own is my baseline. My teaching has to go beyond that level for me to be considered to be "teaching" at all. The further beyond you go, the better you are doing. Good teaching, like good anything, is hard work. Same goes for research, but by and large, students at the undergraduate level don't care about our research and their the ones paying the bulk of the tab, in gross. So on a day-to-day, I mostly think about value added in teaching.
So, an exercise to focus on profs value added I think is important. Now to the technical problems with the method of A&M. I'm sure they counted and added up the numbers correctly, so I don't mean technical in that sense. Rather, I mean technical in the sense that I don't think they have the measurements conceptually straight to begin with. Specifically, the don't seem to be able to differentiate between investment and consumption - one builds stock, the other is just flow.
For example, they find that a senior science prof has value added of near $250,000 per year, whereas a rookie prof has value added of around -$50,000. The senior prof has established, the rookie spent most of the year building a lab, applying for grants, and so forth. His negative value added constitutes investments, whereas the senior prof is earning the net profit from earlier investments. I didn't see anything in the paper that suggested this conceptual differentiation was occurring. I hope that, since this is apparently A&M's first stab at this issue, they'll get better with time. Probably there is some worthwhile reading there, if I can get my hands on the full report, too. You never get all the details in a newspaper article.
The upside I see here, that I mentioned before but will close with, is that such exercises cause us to focus on the value added potential that exists. So will I lament the fact that such-and-so professor can't teach "Medieval Folk Literature of Romania" to three people every year? Without question I will not. Such rarefied material is fine at a private university. But if folks want to insist on public universities and that an education is a public good then the education itself has to result in productive skills.
By the way, I don't buy into the whole public good b.s. I don't think we should have public universities. But that's another post for another day.