Reducing rater bias When subjective performance measures must be used, biases can be reduced through training, feedback, and the proper selection of performance appraisal techniques. Training for raters should involve three steps. First, biases and their causes should be explained. Second, the role of performance appraisals in employee decisions should be explained to stress the need for impartiality and objectivity. Third, if subjective measures are to be used, raters should apply them as part of their training. For example, classroom exercises may require evaluation of the trainer or of videotapes showing workers and working situations. Mistakes uncovered during simulated evaluations then can be corrected through additional training or counseling.