In his book, Essentialism: The Disciplined Pursuit of Less, Greg McKeown has gathered data from more than five hundred people's experience on teams:
I asked them to answer a series of questions about a time when they had worked on a unified team, what the experience was like, what role their manager played, and what the end result was. Then I had them contrast this with a time when they had been on a disunified team and what that was like, what role their manager played, and how it affected the end result.
And here's what he found out:
The results of this research were startling: when there was a high level of clarity of purpose, the teams and the people on it overwhelmingly thrived. When there was a serious lack of clarity about what the team stood for and what their goals and roles were, people experienced confusion, stress, frustration, and ultimately failure. As one senior vice president succinctly summarized it when she looked at the results gathered from her extended team: “Clarity equals success.”