Allan Cox in The Homework Beyond Teamwork provides a comprehensive description of the value-adding team:
The value-adding team is a collective state of mind where ideas are food and puzzlements are challenges. It is where conflict is positive because it is out in the open. Responsiveness is paramount. Whether established department or ad hoc, the team is a thinking organism where problems are named, assumptions challenged, alternatives generated, consequences assessed, priorities set, admissions made, competitors evaluated, missions validated, goals tested, hopes ventured, fears anticipated, successes expected, vulnerabilities expressed, contributions praised, absurdities tolerated, withdrawals noticed, victories celebrated, and defeats over-come. Finally it is where decisions are backed when the boss says yes or no to a particular option.
This description does not specify or validate any particular team structure. My years of experience have convinced me that team structure is of little importance; if the right people are available, structure really doesn’t matter too much; without the right people, no organizational structure will produce the expected results. Every team requires some level of structure if for no other reason than to communicate with other departments. Members of the team cannot go in whatever directions they choose, because there are others depending on their timely performance. There must be a focus on the organization’s objectives.