To work on 360 degree appraisal system, the appraisee has the appraisal form SELF,Sub-Ordinate,Peer,Immediate Superior,HOD,also we can take appraisal from inter department with which that particular employee have a regular transactions and also as you are saying its bank that means the appraisee may deal with external customers like public. So you can also include appraisal from the same also.
Then you design work related KRA's weigthage and Behavioral aspects weightage for rating purpose.
Then you will get appraiser wise weightage as well as final outcome.
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