[pdonis]

> Why cant someone in Africa, or wherever, get a degree in physics from Harvard?

I would put this somewhat differently: why should you need a degree in physics from Harvard to do physics? What value does that credential actually add?

Note, btw, that my own alma mater, MIT, has all of its course materials (lectures, problem sets, selected solutions) available online for free:

https://ocw.mit.edu/index.htm

[wallace_f]

Yea, good point. But some kind of signalling is helpful, no?

And OCW is a great project, but all the course material isn't online. Also, saying to an employer or researcher "I took some OCW courses" isn't a very good signal. A much better signal would be, "I passed such and such examinations with such and such scores." Open competition I think is important.

[pdonis]

> some kind of signalling is helpful, no?

I think calling it "signaling" highlights an important (and troubling) point. Employers and researchers are trying to predict future performance; degrees are supposed to be a measure of one's potential for future performance, and the quality of the institution that granted the degree is supposed to factor into that measure. But over time, institutions have an incentive to reduce rigor and quality in order to cut costs, while still taking advantage of the full perceived value of the degrees they grant based on their past rigor and quality (for example, when charging tuition). I think the common tendency to regard degrees as a form of "signaling" is a tacit recognition that this goes on.

> A much better signal would be, "I passed such and such examinations with such and such scores."

I agree that this would be a much better predictor of potential for future performance, if the institutions grading the examinations and providing the scores were completely unconnected with the institutions that constructed the examinations. (And of course the examinations used for this would have to be different from the ones available over the Internet to everyone.)