Why do you say Carnegie Mellon? I'm assuming it's because they have the Center for Formal Epistemology and a very nice-looking degree program in Logic, Computation and Methodology. But don't some other universities have comparable programs?
Do you have direct experience with the Carnegie Mellon program? At one point I was seriously considering going there because of the logic & computation degree, and I might still consider it at some point in the future.
I mentioned CMU for the reasons you've stated and because Lukeprog endorsed their program once (no idea what evidence he had that I don't).
I have also spoken to Katja Grace about it, and there is evidently a bit of interest in LW themes among the students there.
I'm unaware of other programs of a similar caliber, though there are bound to be some. If anyone knows of any, by all means list them, that was the point of my original comment.
Among my friends interested in rationality, effective altruism, and existential risk reduction, I often hear: "If you want to have a real positive impact on the world, grad school is a waste of time. It's better to use deliberate practice to learn whatever you need instead of working within the confines of an institution."
While I'd agree that grad school will not make you do good for the world, if you're a self-driven person who can spend time in a PhD program deliberately acquiring skills and connections for making a positive difference, I think you can make grad school a highly productive path, perhaps more so than many alternatives. In this post, I want to share some advice that I've been repeating a lot lately for how to do this:
That's all I have for now. The main sentiment behind most of this, I think, is that you have to be deliberate to get the most out of a PhD program, rather than passively expecting it to make you into anything in particular. Grad school still isn't for everyone, and far from it. But if you were seriously considering it at some point, and "do something more useful" felt like a compelling reason not to go, be sure to first consider the most useful version of grad that you could reliably make for yourself... and then decide whether or not to do it.
Please email me (lastname@thisdomain.com) if you have more ideas for getting the most out of grad school!