How important are these, and how often does someone with a good record get spiked because of a bad/meh letter? My publication record is better than many of my tenured colleagues, but I sometimes wonder if they were better known than me in their research areas at tenure time (more invited talks, famous collaborators etc.). A 'meh' letter is probably the kiss of death at an HRM school, but what are MRM committees looking for in tenure letters?
I've noticed that on threads here, people talk about publication requirements for tenure as if that's all that counts.