Participation in organizational decisions is thought to have a number of positive effects on performance and worker attitudes, but it is not clear which elements of participation are responsible for these positive effects. The effects of two elements of participation, upward information input by the worker and the provision of downward knowledge by a supervisor, were examined in a laboratory setting. Thirty-eight male and 49 female undergraduates worked on a task under a performance evaluation procedure that either did or did not allow them to offer information about their performance to an evaluator. A supervisor either did or did not offer information about criteria for evaluation of performance. The subject received either a positive or negative outcome from the evaluation procedure. Upward information flow and downward information flow interacted in their effect on task performance, with highest performance occurring under high upward and high downward information exchange. Performance on a subsequent task increased following downward information on the first task. Upward information flow produced higher ratings of procedural fairness, satisfaction with outcomes, and satisfaction with the supervisor. The results are discussed in terms of their implications for participatory effects and their implications for the design of organizational performance appraisal procedures. (Author)