I've played around with the Big Five model ages ago and found it to be a really good way to look at personality. I especially liked its usefulness for self-assessment - like you say it's easy to self-deceive yourself into thinking that you're much more open and non-neurotic than you really are, but so long as you are honest with yourself it can be a good tool in understanding your own strengths and weaknesses. I hadn't really tried practising it on strangers, though, that would definitely be a useful exercise!

I'm actually in the process of setting up a crowdfunding campaign for a personal project that I'm working on, and if that goes well then I'll be thinking about bringing in more people on board - hence why I asked you about this.

I have to say, the way you're going about this is really impressive in terms of methodology. Most high-level advice in this area that I've seen is full of hand-waving and vagueness, but you've got the whole thing down to a science. Especially the part where you talk about counterfactuals! So many people overlook that.

If you don't mind answering another question, I would appreciate more of your thoughts on this. You've said that you look for particular combinations of traits to fill in particular roles (hacker, inventor, finisher, watchdog, etc.) - what are the traits that you look for in each of them and how exactly do you envision each role's responsibilities within the company? (Is there a set number of such roles that you discovered or do you find yourself inventing new ones as the company evolves?)

Also, it sounds like you've been doing this for a while and probably have quite a few people on board, which would make the dynamic of hiring someone a bit different than if you were just starting out. If you were back to square one and had to consider hiring your first employee or even finding a potential co-founder, how would you approach that?