People can get really stressed in these evaluations because there is so much tied to it. The persons sitting in the corporate office 3,000 miles away may have designed a really super evaluation form, but they don't know squat about the worker in Oregon. The local supervisor should be trusted to deal with this employee personally, using the development and feedback tools needed to get this individual to respond with top performance. Forget tying the evaluation with compensation. Eighty percent of employees think they are in the top quarter of all performers, which even a math novice can see is impossible.
Most employees think they deserve a raise based on their skills.
Explain how continual feedback will be encouraged and that it is believed they come to work every day to do a good job. Then, explain how they must actively seek daily feedback on their work in order to improve. And we need to train managers to be receptive so that employees feel comfortable talking with them about performance. What you want is for people to have the worker's best interests at heart. You want there to be an honest give and take, so that you are working with realities, not assumptions.