Introduction of 360 degree appraisal is no easy task. It requires lot of organisational maturity lest it does more harm than good. By the way, you may read my previous comments on this subject:
Secondly, is every junior capable to assess managerial qualities of his/her manager? Are the juniors capable to interpret correctly the decisions of the managers? For example, while juniors could be sitting at their work desk, manager could be negotiating with the suppliers very well in the board room. In that case, how juniors would know the negotiating abilities of the manager?
Above all essence of Performance Appraisal (PA) just does not lie in measurement of individual performance but organisation's performance as well. For this, you need to identify the direct and indirect costs associated with department. Later you need to assign these costs to each HOD. This is far more important than 360 degree appraisal.
Just now I have given reply to one of the posts on identification of business costs. You may click the following link to refer my reply:
Dinesh V Divekar
23rd January 2015 From India, Bangalore