This paper provides a comparative analysis of behavioral observations made on 152 service providers in a business advisory and professional services firm from 5 distinctly different ratings sources (self, direct reports, peers, supervisor, and clients). Results focused on differences in ratings level and degree of congruence with self-assessments by observer type. The data suggested that service providers and their clients may have a different perceptual frame of reference than do internal observers (e.g., direct reports, peers, and supervisors). Moreover, congruence in self-others' ratings was found to be a significant predictor of performance assessments from the same observer source. Implications of these results for the use of multirater appraisal systems are discussed.