The literature on the partial determinants of performance in organizational contexts, particularly the research on situational determinants, suggests several different variables which may be of importance to appraisal processes as well. This point may be exemplified with regard to the situational factors of task ease/difficulty and situational performance constraints. The importance of contextual factors for understanding the performance appraisal process and evaluating appraisal instruments is critical. The relevance of such contextual variables in the determination of the degree to which rating procedures are susceptible to halo and leniency errors must also be noted. When using contextual information in the evaluation of performance appraisal instruments, it will be necessary to first identify important situational characteristics which exert a strong influence on both mean levels and distributions of observed performance as well as other variables that impact on performance. (JAC)