Throughout most of my career, I've made a big mistake in the way I've lead teams — and wouldn't be surprised if you have, too.

Which is more important to promoting collaboration: a clearly defined approach toward achieving the goal, or clearly specified roles for individual team members? The common assumption — and my personal approach for many years — is that carefully spelling out the approach is essential, while leaving the roles of individuals within the team open and flexible will encourage people to share ideas and contribute in multiple dimensions.

But our research has shown that the opposite is true: collaboration improves when the roles of individual team members are clearly defined and well understood...