You could have given little more information about your query. Are you student or professional? Have you checked this forum for the past replies to the similar queries? Almost six years ago, I had given my reply to the similar query. Check the following link to refer it:
While 360 degree appraisal may give semblance of democracy, the purpose of Performance Appraisal (PA) or Performance Evaluation (PE) is measuring what deserves to be measured. What if you start 360 degree appraisal however, some important organisational performance ratios are not measured?