The impact of mixed-anonymity on brainstorming performance: Evidence from field experiments

Generating innovative and valuable ideas is essential for organizational competitiveness, and structured ideation formats are widely used to support creativity and idea generation of individuals, teams, and organizations. One such format is nominal brainstorming, in which participants generate ideas independently rather than through group interactions. Previous research has produced mixed results regarding the impact of anonymity in such individual idea-generation settings. Anonymous formats may reduce evaluation apprehension but can also lead to free riding, while non-anonymous formats promote accountability yet might increase the fear of negative evaluation. To clarify these conflicting findings, this study examines a novel mixed-anonymity approach in which participants generate ideas independently and anonymously, but the identities of those with the highest-rated ideas are subsequently revealed. We investigate the effects of mixed-anonymity on individually generated brainstorming outputs in two field experiments. The first adopts a between-subject design (N = 216), randomly assigning participants to anonymous, non-anonymous, or mixed-anonymity conditions. The second follows a within-subject design (N = 192), exposing each participant to all three conditions. In both studies, participants engaged in nominal brainstorming tasks. Ideation outcomes were measured by quantity, novelty, and user value. Additionally, we assessed evaluation apprehension and free riding as potential mediators. Our between-subject experiment did not demonstrate significant differences in idea quantity, novelty, or user value among the three anonymity conditions. Conversely, the within-subject experiment revealed significantly higher idea novelty under mixed-anonymity conditions compared to anonymous and non-anonymous conditions, but no significant effects on idea quantity or user value. Contrary to initial hypotheses, the proposed mediators, evaluation apprehension and free riding, did not explain these results. These findings refine the current understanding of anonymity in nominal brainstorming by showing that mixed-anonymity does not yield consistent effects across experimental settings. Overall, this study indicates that the role of mixed-anonymity in individual idea generation is contingent, not as straightforward as existing theorizing based on evaluation apprehension and free riding would suggest.