I agree the post is a bit over the top. From what I saw, At the end of the minicamp, everyone, including myself, felt really good about how it had gone. The attendees all felt that they had gotten really valuable lessons out of it. But of course that feeling so short after learning the material isn't that strong of evidence. I agree better measurement would be a really good thing, though I'm not certain how you would go about that.

Here are some things I currently think I got out of the minicamp and some reasons why:

1. The realization that having a more accurate model of my mind could be quite valuable and that science had more useful things to say about my brain than just the heuristics and biases literature. In particular, I'm thinking of the research on how (some) emotions work (affective neuroscience) and the research on motivation. Luke and Academian were fairly convincing that their knowledge of these fields allowed them to be more successful. I also don't think I had been taking the idea that my brain is composed of many subprocesses many of which influence my behavior but are mostly opaque to my conscious mind seriously enough for practical purposes.
2. I realized that being in close contact with smart, relatively rational people trying to optimize themselves makes optimizing yourself quite a bit easier. It's much easier to approach people for ideas on how to optimize and the quality of ideas are better. It's also more fun! This has made me more excited about the Seattle LW group.
3. I realized that being fashionable is more important than I thought (I just hadn't given it very much thought before). I also got very actionable information on how to improve my fashion (general rules, ways to learn more, how to go about buying stuff, etc.). I also realized I was signaling stuff I didn't want to signal, so I'm changing my general look. Basically, luke went through a list of 'don'ts' and my typical style was explicitly mentioned.
4. I figured out I should be putting more energy into my work and less on other things. I've started collecting data on my productivity and trying to train myself to notice when I'm getting distracted and to do something about it.
5. Anna had a lot of useful seeming tricks for getting yourself to engage in actual thinking when you need it to (recognizing characteristic thinking substitutes, noticing various kinds of warning signs, etc.). I've used a at least two of these to change my mind on something at work.
6. The mere act of writing down important goals and problems and asking obvious seeming questions can generate useful insights. Further discussion with reasonable people generates even more insights. This happened to me and others several times. The Seattle LW group has done this once already and it was pretty useful, so we're going to focus more on it in the future.
7. I realized I hadn't paid nearly enough attention to the notion of an Ugh Field. I noticed I have been (and probably continue to be) heavily affected by something along these lines. This concept has helped me get a lot of stuff done that I otherwise wouldn't have.

There's more, but I'll leave it there for now and maybe come back to it.

One thing that is being doing, that does provide data is that people are submitting before and after fashion photos a month after the camp (the aim is to get people to follow through on implementing fashion changes). Obviously this isn't perfect, but it does provide some data about how effective that part of the camp has been.