It's not entirely clear whether or not they're counting contractors and those in traditionally high turnover roles like support and commissions-based remote sales.<p>If the turn over for technical staff is indeed greater than industry and location average (and I suspect it isn't), then I think the reason is a bit simpler than most suspect: especially with less experienced engineers (0-3 years out of university), working for a company like Google quickly builds more career capital (as a result of strong engineering culture, social proof, ability to do fairly unique work, etc...) as opposed to same length stay elsewhere. In other words, it becomes easier for many to go elsewhere if they seek greater responsibility, better projects, flexibility (e.g., being able to work remotely full time), equity/salary, to move from SDET or SRE to a pure software engineering role, to get a position at a growing company that would have previously passed on them, and so forth...<p>While I'm inclined to believe commentators promotion mechanisms on Google's technical ladder could be improved (and I am sure this is something Google is working to improve continuously), I don't necessarily think this kind of turnover is unhealthy. If a great person leaves and it's apparent to everyone that they've been overlooked and Google <i>should have</i> promoted them <i>before</i> they attempted to resign, it helps show a pattern of what kind of workers are overlooked; if a person leaves and the opposite is true (e.g., they weren't performing in a way that warranted a promotion, they weren't technically qualified to take on a project of their choice, etc...) then it serves a safety mechanism: those unhappy with their role leave -- meaning the average worker is happier with their role than otherwise.