How could they perform this analysis? Does every engineer at Google excel? Is their revenue a permanent hockey stick? If so, the process is working. If not, it'

How could they perform this analysis? Does every engineer at Google excel? Is their revenue a permanent hockey stick? If so, the process is working. If not, it's not. But if they have any poor engineers, their process clearly doesn't work so conclusively. Because those engineers passed their process. And they have no control group, unless they've secretly been hiring a group of engineers without asking them these sort of questions (or ignored the results for a group). I just don't see how Google could determine the process works without studying what happens if they don't do it.