Abstract
How does tactical, organizational, and other information pass between armed groups? Existing research overwhelmingly focuses on observable links like alliances, training camps, and shared foreign patrons. Yet, information is also passed via organizational lineage through processes of splitting, merging, and membership migration. Focusing on organizational splitting in particular, we test this argument with a case study of Republican armed groups in Ireland and Northern Ireland, and by statically forecasting how organizational linkages shape patterns of tactical diffusion between groups. The results confirm our expectations and they underscore the critical role of organizational lineage in the diffusion of information between groups. This has important ramifications for how researchers model the dynamics of armed groups particularly as they relate to operational capacity, tactical innovation, and future trajectory.