Scott Keller, Mary Meaney [Archive.org URL]

[Books often] say that you have a limited period to achieve full productivity as a leader and that if you don’t make it in time, you are doomed. The evidence doesn’t support these claims: 92 percent of external and 72 percent of internal hires take far more than 90 days to reach full productivity.14 Sixty-two percent of external and 25 percent of internal hires admit that it took them at least six months to have real impact.