With the evolution and development of appraisal systems, a number of tools and techniques of performance appraisal have been developed. Firstly, there are graphic-rating scales which compare individual performance to an absolute standard. In this method, judgments about performance are recorded on a scale. This is the oldest and most widely used technique. This method is also known as linear rating scale. The appraisers are supplied with printed forms, one for each employee. These forms contain a number of objectives and behavior- and trait-based qualities to be rated (like quality, volume of work, job knowledge, dependability, initiative and attitude). Rating scales are of two types: continuous rating scales and discontinuous rating scales.

In continuous order like 0, 1, 2, 3, 4 and 5, the appraiser assigns the points to each degree. Performance regarding each character is known by the points given by the rater. These points are added up to find out the overall performance. Employees are ranked on the basis of total points assigned to each one of them. One reason for the popularity of the rating scale is its simplicity, which permits many employees to be quickly evaluated. Such scales have relatively low design cost and high incase of administration. They can easily pinpoint significant dimensions of the job. The major drawback of these scales is their subjectivity and low reliability. Another limitation is that the descriptive words often used in such scales may have different meanings to different raters.

Another popular and effective method of performance appraisal is employee ranking. Under this method the employees are ranked from best to worst on some characteristics. The rater first finds the employee with the highest performance and the employee with the lowest performance in that particular job category and rates the former as the best and the latter as poorest. Then the rater selects the next highest and next lowest and so on until he rates all the employees in that group.