> In general, folks who switch jobs every two years are the folks who are not getting offered big raises by their current companies
I think the selection bias works in the opposite way that you assume. The employees switching jobs every two years are the ones that are in higher demand and are easily able to get and pass job interviews. They're the ones that better know their market value and the ones that are most easily able to leverage one offer against another to negotiate a better offer.
It's this phenomenon that leads companies to even consider morale zapping policies like always laying off the bottom X% of their employees. The theory behind that idea is that if you just allow other companies to poach your top employees, you'll be left with nothing but your bottom employees who have trouble landing other work. Having seen this play out in a few of my employers, I believe it's a very real danger, though forced layoffs are a really terrible way to deal with it.
I think the selection bias works in the opposite way that you assume. The employees switching jobs every two years are the ones that are in higher demand and are easily able to get and pass job interviews. They're the ones that better know their market value and the ones that are most easily able to leverage one offer against another to negotiate a better offer.
It's this phenomenon that leads companies to even consider morale zapping policies like always laying off the bottom X% of their employees. The theory behind that idea is that if you just allow other companies to poach your top employees, you'll be left with nothing but your bottom employees who have trouble landing other work. Having seen this play out in a few of my employers, I believe it's a very real danger, though forced layoffs are a really terrible way to deal with it.