All team members must have clearly defined roles and be fully engaged. A person is selected for a team for a reason and must therefore take up an active role. A football coach does not pick 11 players and know that he does not intend to give a role to all of them. Each has a role to play and should be fully engaged. Sometimes the argument is used that simple observation is a good way to bring a junior or less experienced member of staff on board, with no active role. as a learning exercise. This is of limited value and by all means bring such people on board, but they learn by doing so this is not an excuse not to give them an active role and specific tasks to complete.
And what is more fresh eyes might bring a different perspective and change the team dynamic when their opinion is allowed to be expressed.
This is perfectly illustrated in the film The Sum of All Fears in which Ben Affleck plays a "de=aged" Jack Ryan who at the time is a junior CIA Analyst. Early on in the film the former Russian leader dies suddenly and is replaced by a new leader played by Ciaran Hinds (Mace Raydor in Game of Thrones) and the CIA don't know anything about him but as it happens Ryan had done a thesis on him and even met. him.
The CIA were concerned as to whether they had another Stalin or a Gorbachev on their hands and the head of the CIA, played my Morgan Freeman, pulls Ryan in to a high level meeting. Ryan even has to borrow a tie and seemingly is well out of his depth. In the meeting they all pretty much come to the consensus that he is a new Stalin and Ryan stands up to disagree. Now here is the point. His boss (Freeman) tells him to sit down and says
"When I invited you to the meeting I didn't actually expect you to speak".
So if that was the case what was he doing there? Keeping a seat warm. Unless he has a role there is no point in him being there.
As the film develops it appears initially that Ryan was wrong, but it later became more than apparent that he was right and in the end he stopped an escalation that would have led to the Third World War.
The correct call was made because a junior member of the team spotted it.
For a number of years I worked initially under and later alongside a guy who led teams in a variety of fields to fulfill a number of purposes and one of his clear mottos was that he always aspired to full employment of his people – in other words full engagement and involvement, without exception.
So make sure your team is engaged and working towards a common purpose and completing their tasks to meet the goals. Don't carry any passengers. If you have somebody new or inexperienced give them simpler tasks initially - such as data input - but get them engaged and as they grow in confidence and competence bring them on accordingly.
There is no room for slackers in a team
As always stay safe and well