Shared Leadership from Rome to Mars

Leslie DeChurch, Alina Lungeanu, Megan Chan, and Noshir Contractor

Manuscript under review; please contact Megan for a working draft

Abstract: This study examines the emergence and stability of shared leadership in two distinct contexts: NASA space analog teams preparing for future Mars missions and leadership arrangements in Ancient Rome (32-491 CE). Despite growing enthusiasm for shared leadership in modern organizations, little is known about its natural emergence and stability. Using observational data from 13 NASA crews and historiometric data from the Roman Empire, we find shared leadership frequently emerges in both contexts. However, our analyses reveal an unexpected pattern: while both hierarchical leadership (single leader) and shared leadership with three or more leaders tend to persist over time, shared leadership arrangements with exactly two leaders are uniquely unstable. This “dyadic instability” appears consistently across both modern and historical datasets, suggesting an inherent dynamic in human organization. These findings have important implications for contemporary organizations experimenting with co-leadership models, particularly at the CEO level, and suggest the need for additional organizational support mechanisms when implementing dyadic leadership structures. Our results contribute to leadership theory by identifying a critical threshold in shared leadership arrangements and offer practical insights for organizations considering co-leadership models.

Related work:

DeChurch, L., Lungeanu, A., Chan, M. (2025, Jul 25-29). When Two is Too Many and Not Enough: Shared Leadership in Ancient Rome (32 to 491 CE). [Conference Presentation]. Academy of Management, Copenhagen, Denmark.

Winner of the Sage Publishers Award for best Management History Division paper in leadership

Markov transition matrix of leadership transitions in NASA space analog crews, showing that co-leadership is unstable

Markov transition matrix of leadership transitions from the Imperial Period of Rome, showing that co-leadership is unstable

Research supported by NASA awards NNX15AM32G, 80NSSC18K0221, and 80NSSC18K0276

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