Final answer:
The performance appraisal system described is the forced distribution method, which allocates employees into predefined performance categories based on the assumption of a normal distribution of performance levels.
Step-by-step explanation:
The performance appraisal system that requires supervisors to classify their employees into specific categories such as "top one-fifth" or "second one-fifth" is the forced distribution method. This method assumes that the performance of employees will conform to a normal distribution. Therefore, only a certain percentage of employees can be placed in each performance class, often creating a competitive environment and aiming at differentiating employees' performances in a quantifiable manner.
In contrast to the 360-degree feedback appraisal, where the assessment comes from multiple sources including supervisors, peers, and the employee themselves, the forced distribution method is a singular, top-down approach predominantly utilized by management. Performance appraisals are vital for organizational development, and they serve to motivate employees, identify training needs, and document the basis for performance-related decisions, such as promotions or terminations.