Please take this article into consideration before implementing a review process.
While the idea sounds good, the truth is the review process is largely broken. It causes more harm than good as managers tend to use it to focus only on negatives or petty discord, and peers/subordinates use it as a way to (relatively safely) retaliate against those above them. As someone currently dealing with a manager who received largely negative reviews, and her boss who is largely making no effort to help her, I have to say that unless you have the right behaviors and values being practiced, it’s a paper-pushing exercise that yields no benefit to company or employee.
Alternately, consider a straightforward, transparent and objective measure of performance. Manager and employee write the goals together, and then check did they meet their goals. Do this on an ongoing basis not quarterly or annual. Studies have shown reviews favor the last 90 days because our brains are biased to more recent activity.
If they met the goals, then good; if no, then examine why, and assist with coaching to improve for the next round. If you are not tying worthwhile compensation bonuses or increases to the process, it is largely symbolic and a dated display of authority. Employees typically find them degrading…it smacks of getting grades in elementary school.
Further, are you conducting reviews to serve a material purpose or because “that’s what businesses are supposed to do”? What is the true benefit to the business for doing these?