Performance Appraisal

Certainly, the most popular method of evaluation used in organizations today is the graphic rating scale. One study found that 57 percent of the organizations surveyed used rating scales, and another study found the figure to be 65 percent. Although this method appears in many formats, the supervisor or rater is typically presented with a printed or online form that contains both the employee's name and several evaluation dimensions (quantity of work, quality of work, knowledge of job, attendance). The rater is then asked to rate the employee by assigning a number or rating on each of the dimensions. An example of a graphic rating scale is shown in Table 8.1.

By using this method, if we assume that evaluator biases can be minimized, it is possible to compare employees objectively. It is also possible to examine the relative strengths and weaknesses of a single employee by comparing scores on the various dimensions.

However, one of the most serious drawbacks of this technique is its openness to central tendency, strictness, and leniency errors. It is possible to rate almost everyone in the middle of the scale or, conversely, at one end of the scale. In order to control for this, some companies have assigned required percentage distributions to the various scale points. Supervisors may be allowed to rate only 10 percent of their people outstanding and are required to rate 10 percent unsatisfactory, perhaps assigning 20 percent, 40 percent, and 20 percent to the remaining middle categories. By doing this, a distribution is forced within each department. However, this procedure may penalize a group of truly outstanding performers or reward a group of poor ones.