How can we describe(analyze) the differences between evaluating team performance and individual performance?
Managers pointed out that there was not an effective process for assessing the work of teams.
This is an interesting question, but I disagree with the opinions of the managers you reference. This is an issue that arises not only in business, but also in teaching.
In the workplace, what may always be assessed is the end result of the team's efforts. What was the goal? Was it met? Was the team supposed to produce a good or a service? Were they supposed to solve a problem or be responsible for training new employees? Were they expected to achieve a certain number of sales? A team's performance can always be assessed in this way.
I frequently hear students complain about group projects. One basis of complaint is that there are slackers in any given group and no one wants to carry their weight or be downgraded because of them. I tell my students that in the workplace, there will be slackers, too. And that management will not care. Each student must choose whether his or her team will perform poorly or if he or she will overcompensate for the slackers, just the way it works in the workplace.
I would not think it reasonable for individual employees to have annual or semi-annual evaluations based solely on team results, but there could very well be workplaces where that happens. If one is on a team and everyone is responsible for results, the employee has the same choices my students have, to accept the consequences or to pick up the slack for the slackers.