In a lot of fields a M.S. is a requirement to start a PhD. It has nothing whatsoever to do with coursework. Instead, it's a matter of research experience. (Also

In a lot of fields a M.S. is a requirement to start a PhD. It has nothing whatsoever to do with coursework. Instead, it's a matter of research experience. (Also, at least in my field, you usually do your B.S., M.S., and Ph.D. at three different institutions.) At least in the geosciences, it's something like: B.S.: Basic coursework and a senior thesis * Senior Thesis: "Here's a well-defined problem, here's how I'd start, why don't you think about how you'd do it and go solve it" M.S.: A class or two and a Masters Thesis * Thesis: "Here's an relevant, unsolved problem. Go solve it." PhD: Research (and lots of seminars) * Dissertation: "Come up with 3 relevant, unsolved, and interesting problems. Then solve all three of them." The big difference is really in finding your own interesting problems (and often finding funding for them as well) as opposed to being handed a problem.