This research develops a two-level model based on hypotheses, which concern relationships among role ambiguity, role conflict, job involvement and salesperson performance at individual level and collective sale self efficacy, customer orientation and competitive climate at sale unit level in Iranian food industry. Data was drawn from 482 sales people in 30 companies , using a 51-item self-reported questionnaire. Research model was tested in disaggregation, aggregation and multilevel approaches. The results from three approaches were different. Multilevel modeling analysis revealed that role ambiguity and role conflict have negative effects, but collective sale self efficacy and job involvement have positive effects on sales person performance. Results also showed that collective sale self efficacy has positive moderation effect on the relationship between job involvement and sales person performance. Collective sale self efficacy indicated positive moderation effect on the relationship between job involvement and sales person performance and negative moderation effect on the relationship between role conflict and sales person performance.
