Google set out to determine what makes a manager great at Google. But first, a research team tried to prove the opposite: that managers actually don’t matter, that the quality of a manager didn’t impact a team’s performance. This hypothesis was based on an early belief held by some of Google’s leaders and engineers that managers are, at best, a necessary evil, and at worst, a layer of bureaucracy.

The team defined manager quality based on two quantitative measures: manager performance ratings and manager feedback from Google’s annual employee survey. This data quickly revealed that managers did matter: teams with great managers were happier and more productive.

But knowing that managers mattered didn’t explain what made managers great. So the team asked employees about their managers. By going through the comments from the annual employee survey and performance evaluations, the team found ten common behaviors across high-scoring managers. The researchers also conducted double blind interviews with a group of the best and worst managers to find illustrative examples of what these two groups were doing differently.