Abstract: This research used the multitrait multirater matrix to analyze two kinds of bias: halo effect and egocentric effect Professional football players were rated in this research The performance traits of four different positions were obtained using Critical Incident Technique The basic correlation coefficient was the correlation among position traits rated by 45 subjects after watching one football match Eight subjects who were divided into two groups watched part of one cassette while part of them changed their rating standard The correlation coefficients among the rating results of each trait were computed and then sorted into a multitrait multirater matrix The result showed that halo effect could be identified explicitly in multitrait multirater matrix, and the raters showed egocentric effect in some specific traits of different positions

Key words: performance appraisal, halo effect, ego centric effect, multitrait multirater matrix