A performance evaluation is annual review of an employee's overall contributions to the company by his or her manager. Performance evaluations, evaluate employees skills, achievements and goals. A manager evaluates an employee's work behaviour by comparing it with preset standards, documents the result of the comparison and used the result to provide feedback to the employees to show where their improvement where needed and why. performance evaluations are used to determine who needs what training, and will be promoted, demoted, retained , or fired. When a manager gives a particular employee a high or low rating, a manager must give a reason as to why they gave the rating. the comment must be actionable if the rating is low.