As a supervisor who is in charge of a team, you must find the right mix of team members, while trusting their abilities to fit into their roles. By defining the roles in advance you can slot your team members into the most appropriate roles to get the job accomplished. Being in charge of a group requires the supervisory talents to organize employees and to prioritize work. Planning for supervisors is the best quality you need to define team roles.
The simple fact is that all of the writing about the distinctions between managers and leaders, about whether one is better than the other, about whether we need both, and about whether organizations need more or less of one or the other entirely miss the point.
A project or challenge comes up and many people, without thinking, immediately form a team to research, solve the problem and implement the solution. Teams can be a very powerful way to solve problems and implement massive improvements. But teams aren’t the right answer to every situation