c 360 appraisals can be biased in many ways eg.
if i see my collegue doin really well, (and i am jealous )so as soon as i will get an opportunity to give a feedback.i mite try to pull him down ...u no.........i mite on purpose give a wrong feedback just to pull him doewn...........apart from that.....to improve overall scores collgues may join hands to rate each other high........and stuff like that..........otherwise also.....it usulaly happens if eg, i dont like X, then chances are that i will not talk or rite good abt him.......u no how personal issues can effect our job so..........