Stepping back from the Scrum team best practices from team’s I ended up using Richard Hackman’s studies on teams. He identified 6 enabling conditions for team effectiveness:

1. One, is the group a real team, with clear boundaries, interdependence among members, and at least moderate stability of membership over time?
2. Does the team have a compelling direction, a purpose that is clear, challenging, and consequential — and that focusses on the ends to be achieved rather than the means the team must use in pursuing them? 
3. Does the team have the right people on board? 
4. Does the team’s structure — its task, composition, and core norms of conduct — enable rather than impede teamwork? 
5. Does the team’s social system context provide the resources and support that members need to carry out their collective work? 
6. Is competent coaching available to help members get over rough spots and take advantage of emerging opportunities, and is such coaching provided at times in the team life cycle when members are most ready to receive and use it?

Research confirms that the presence of these conditions — real team, compelling direction, enabling structure, supportive context, and competent coaching — enhances team performance effectiveness. In a study of 64 analytic teams in the U.S. intelligence community, for example, Hackman and O’Connor (2004) found that 74 percent of the variance on a reliable performance criterion was controlled by these conditions.