If you're like most organizations you ask your managers to assign a rating to employees during the performance review process. No one likes to be rated and most people don't like assigning ratings. Read a blog post we've written on ratings for more in depth exploration on this often debated topic.
Now back to the fact that you may need to have a rating system. Because we promote the fact that what is achieved in the job is just as important as how it's acheived we suggest considering a system that simetaneously rates both Job Competence (job responsibilities, skills and goal achievement) AND Behaviors.
The advantage of using a dual rating system is that it can more accurately reflect the actual performance contributions of the individual being rated. Case in point: the highly competent employee who accomplishes all of their job responsibilities yet treats their colleagues like second class citizens. In otherwords, the work gets done but their behavior towards co-workers is deplorable. On a rating scale of 1 - 5, five being the highest, the manager might be apt to give the employee a 4. Discounting the rating by one point to account for the employee's lousy treatment of colleauges. In reality the Job Competence really is a 5, the highest rating and the Behavior rating should be a 1 or 2 at most. Click here for this example.