Make sure the committee is working on the basis of evidence. Coffee room conversations are not evidence. Personal friendships are not evidence. The opinion of an economist about the standard of publications of a sociologist is not evidence. Anonymous student complaints are not evidence.
Natural justice is all-important.
With the exception of referee's reports, no negative evidence about a staff member's performance should be permitted to be introduced into staff committee unless the staff member is aware of that negative information and has had a chance to respond. This is most important with student complaints. No student complaint can form the basis of an assessment of a staff member unless it has been drawn to the staff members' attention . Be VERY vigilant that a Head of School does not introduce into their report on the staff member at the meeting, material that the staff member does not know about. Performance evaluation and promotion applications must be made against the written criteria.