How rot draft a good performance appraisal form?...

I am as a banker is confronted with assorted problems when it comes to a question of appraising a person purely objectively not letting any other considerations than his pure performance influence the appraisal of the person in question?

The real problem with is that most people appraise with preconceived thoughts or images of the persons they are appraising, and as a result it becomes totally subjective and both the appraisers and appraisees lose and the bigger loser is the organization both work for as a matter of fact.

Is there anything that help overcome this type problems the kind that is not spelled out but is the real case in many organizational circumstances?