[FireBeyond]

I'm not sure how you can evaluate 30 people you don't interact with closely.

NIMS, the National Incident Management System, talks of ICs having between 3-7 direct reports, when there is a need to be connected to what they are doing, because beyond that, you can't reconcile things easily.

[The_Colonel]

I don't know the exact process, but AFAIK managers pull the evaluation from many people you do interact with (outside and inside the team).