Hi,
Operationally, there is NO difference between the two.
Both lead to your/organization's judgement as to the performance of the individual in question. Appraisal sounds more refined than the Evaluation, in that one is to "measure" against a yard-stick and the other is to judge (perhaps even without "measuring".)
In that sense Appraisal tend to be understood as more "objective" and the Evaluation" appears to be more "subjective". But this need not necessarily be so and how it will be depends upon the individual who appraises or evaluates, his training, his competence on the job and his own personality strengths and weaknesses.
It is the system of appraisal and the training of the appraisers and the organizational culture that decide if the exercise proves helpful or not. In many cases, in the name of "performance appraisal" what actually takes place is "personal appraisals". That would be a disaster. In appraisal the priority is to appraise the Performance ahead of the Person.
It is indeed enough to conduct appraisals for the "waiers" on an yearly basis, but the performance must be reviewed, preferebly every three months for very many reasons and that applies to all levels of appraisals
Has your query been now answered?
Regards
samvedan
October 2, 2006