There was an interesting article recently in the Times newspaper (London) on the issue of self-appraisals. According to the article, staff turnover dropped quite a bit at one company after they used self-appraisals.
This is not surprising because self-appraisals effectively take power away from the boss (effectively getting rid of the boss). No wonder people are happier and stay on.
(Email me your comments at chetan@cvdhruve.com)