[amaks]

"At Microsoft, folks are given the hint early enough that they can explore other internal options before leaving the company entirely."

Except that it doesn't work. No internal hiring manager will ever allow the interview loop/transfer for the internal candidate with the score 4 or 5 (I think those are the lowest scores in the current model:-). In 99.9% of cases those unlucky who got 5 get laid off by the next review period.

[robododo]

I've actually seen one person move after a 5. A poor data set, admittedly. It does happen, though.