The final element of Nadella’s plan to inspire collaboration at Microsoft was to change the way the company evaluated employees. Microsoft had a long history of performance evaluations called “stack rankings” that pitted its employees against one another. The dreaded system forced managers to rate their reports on a bell curve. No matter how good a team was, or how evenly talented its members were, a preordained number of people would get great reviews, and a set amount would get poor reviews.

“Let’s say your whole team was the same skill level; you still had to force it,” one former senior manager told me. “Somebody was going to get a huge bonus, and someone’s going to get borderline fired. Not that extreme, but it’s going to happen.”

Because of this, employees sabotaged one another. And the company’s most talented people went out of their way not to work with one another. “Microsoft superstars did everything they could to avoid working alongside other top-notch developers, out of fear that they would be hurt in the rankings,” the Vanity Fair article said. “Microsoft employees not only tried to do a good job but also worked hard to make sure their colleagues did not.”