Performance appraisal is a systematic process of evaluating an employee's job performance and productivity. It helps in determining the strengths and weaknesses of an employee, identifying areas of improvement, and making decisions related to promotions, training, and rewards. There are several methods of performance appraisal, and three commonly used methods are the man-to-man comparison method, straight ranking method, and check list method.

1. Man-to-man comparison method:
This method involves comparing the performance of each employee with that of every other employee in the same job category. It requires the evaluator to rank employees from the best performer to the worst performer based on their overall performance. This method helps in identifying the top performers and the underperformers, making it easier to reward and develop employees accordingly.

2. Straight ranking method:
In this method, employees are ranked from highest to lowest based on their performance. The evaluator assesses the performance of each employee and assigns them a rank. This method is simple and easy to understand but may not provide detailed information about individual strengths and weaknesses. It is commonly used in small organizations where the number of employees is limited.

3. Check list method:
The check list method involves the use of a predefined list of traits or behaviors that are considered important for successful job performance. The evaluator rates the employee on each trait or behavior using a scale or checklist. The checklist may include items such as communication skills, problem-solving abilities, teamwork, and time management. This method provides a structured approach to performance appraisal and allows for a comprehensive evaluation of various job-related factors.

All three methods - man-to-man comparison, straight ranking, and check list - are valid and widely used methods of performance appraisal. Each method has its advantages and disadvantages, and organizations may choose to use a combination of these methods or customize them to suit their specific needs and requirements. The choice of method depends on factors such as the size of the organization, the nature of the job, the availability of resources, and the desired level of detail in the evaluation process.

In conclusion, performance appraisal is a critical process in evaluating employee performance, and the man-to-man comparison, straight ranking, and check list methods are commonly used to assess and measure performance. These methods provide valuable insights into employee performance and help organizations make informed decisions regarding employee development and rewards.