Written performance rating reports shall be completed on forms devised by the personnel director at least annually for all department heads and employees in the classified service and at least quarterly for all employees serving their probationary period. Supervisors shall review each report form with the employee concerned and the employee shall sign the form acknowledging that this review has taken place. Employee’s signature does not necessarily constitute agreement with supervisor’s rating. The personnel director shall maintain a record of each employee’s ratings. The rating reports may be used as measures of an employee’s fitness to advance in pay and to determine the order for layoffs as outlined in Section 2.36.280. (Prior code § 2704.8)