I think this will vary a lot depending on what kind of work you're aiming to do, but I could imagine a training programme for e.g. promising young grantmakers being very helpful

Charity Entrepreneurship tries to do this for entrepreneurs

There's the CFAR workshop, but it's just a 4 day program. (Though it would take longer to read all of Yudkowsky's writing.)

I'm no expert, but in some plausible reading, US Military training is primarily about cultivating obedience and conformity. Of course some degree of physical conditioning is genuinely beneficial, but when's the last time a Navy Seal got into a fist fight?

For most of the EA work that needs to get done (at the moment), having an army of replaceable, high-discipline, drones is not actually that useful. A lot of the movement hinges on a relatively small number of people acting with integrity, and thinking creatively.

Instead of intense training processes, EA at the moment relies on a really intense selection process. So the people who end up working in EA orgs have mostly already taught themselves the requisite discipline, work ethic and so on.

I recently read Can't Hurt Me by David Goggins, as well as Living with a SEAL about him, and found both pretty appealing. Also wondered whether EA could learn anything from this approach, and am pretty sure that this is indeed the case, at least for a subset of people. There is surely also some risk of his "no bullshit / total honesty / never quit" attitude to be very detrimental to some, but I assume it can be quite helpful for others.

In a way, CFAR workshops seem to go in a similar-ish direction, don't they? Just much more compressed. So one hypothetical option to think about would be to consider scaling it up to a multi-month program, for highly ambitious & driven people who prioritize maximizing their impact to an unusually high degree. Thinking about it, this does indeed sound at least somewhat like what Charity Entrepeneurship is doing. Although it's a pretty particular and rather "object-level" approach, so I can imagine having some alternatives that require similarly high levels of commitment but have a different focus could indeed be very valuable.

I recently learned about Training for Good, a Charity Entrepreneurship-incubated project, which seems to address some of these problems. They might be worth checking out.

I think this is a great exercise to think about, especially in light of somewhat-recent discussion on how competitive jobs at EA orgs are. There seems to be plenty of room for more people working on EA projects, and I agree that it’s probably good to fill that opportunity. Some loose thoughts:

There seem to be two basic ways of getting skilled people working on EA cause areas:
1.  Selectively recruiting people who already have skills.
2. Recruiting promising people who might not yet have needed skills and train them. 

Individual organizations can choose both options, depending on their level of resources. But if most organizations choose option 1, the EA community might be underutilizing its potential pool of human resources. So we might want the community in general to use option 2, so that everyone who wants to be involved with EA can have a role—even if individual EA organizations still choose option 1. For this to happen, the EA community would probably need a program whereby motivated people can choose a skillset to learn, are taught that skillset, and are matched with a job at the end of the process. 

Currently, motivated people who don’t yet possess skills are placed into a jumble of 1-on-1 conversations, 80k advising calls, and fellowship and internship listings. Having those calls and filling out internship and fellowship applications takes a ton of time and mental energy, and might leave people more confused than they were initially. A well-run training program could eliminate many of these inefficiencies and reduce the risk that interested people won’t be able to find a job in EA. 

We can roughly rank skill-building methods by the number of people they reach (“scale”), and the depth of training that they provide. In the list below, “high depth” skill development could lead to being hired for that skill (when one would not have been hired for that skill otherwise), “medium depth” as warranting a promotion or increase in seniority level, and “low depth” as an enhancement of knowledge that can help someone perform their job better, but probably won’t lead to new positions or higher status.

• Internal development within organizations, like Aaron Gertler mentioned (small scale, medium depth)
• Internship/fellowship programs (medium scale, medium depth)
• One-off workshops and lectures (small scale, low depth)
• Cause area-specific fellowships, like EA Cambridge's AGI Safety Fellowship (large scale, low depth) 
• A training program like the one I described above (large scale, high depth)
• An EA university, as proposed here (large scale, high depth)

If we choose option 2, we probably want large scale, high depth ways to train people. I’m interested in hearing people’s thoughts on whether this is a good way to evaluate skill-building methods.

One caveat: there’s a lot more interest in working for the military than there is in working for EA orgs. Since this interest already exists, the military just needs to capitalize on it (although they still spend lots of money on recruitment ads and programs like ROTC). The EA community doesn’t even have great name recognition, so it’s probably premature to assume that we’d have waves of people signing up for such a training program—but it’s possible that we could get to that point with time.

I think a related question is:

"How much less effective would a project have to be for it to be worth it in terms of possible effectiveness and training value?"

ie Is it worth there being moonshot with lower EV than say GiveDirectly, which might find great leaders?

This seems related to Ben Todd's recent comment that EA has a leadership bottleneck. If true, why is training more leaders not a top priority? Maybe I'm misunderstanding something. https://twitter.com/ben_j_todd/status/1423318856622346249

Rethink Priorities has an internship program.

If I recall correctly, they got 700 applications in the first round so there could be a lot more funding for internship programs which have space to take that funding.