[ChuckMcM]

It is a fair point that you have to consider the null hypothesis. My experience, and granted its really only about a dozen startups where I actually know the full details of the deal, are either a "huge" win over an established (already public) company or a "huge" loss (the go out with no additional value). And I happen to know that in this specific case folks that were senior engineers at Google and are now senior engineers at Box, and at least one of them is happy they didn't choose to stay at Google. But like anything, Box could IPO and fall through the floor like Zynga (I doubt it, but it could) or GroupOn. Or it could do a Facebook and fall for a while and then recover quite nicely. So the play isn't over yet as they say. In my own experience if Google hadn't repriced everyone's ISO shares I would have made very little money on them after they had vested and I exercised them.

The key though is that its really really hard to compute the expected value of a share, even with Black-Scholes, such that you know what the right answer is :-)

I will say that I have not yet met anyone driving their life based on expected value of their choices who is really happy. I find that strange sometimes because when it is a conscious choice you would think they would be happy to be doing what they want, but so far haven't found anyone.