While much is known about the intra-community diffusion of Information Systems (IS) innovations, less is understood about how diffusion unfolds across communities separated by temporal and institutional contexts. This study examines the diffusion of a complex IS innovation, Enterprise Architecture (EA), over 30 years across two distinct communities: a “first mover” community consists of 50 U.S. state governments and a “late follower” community consists of 63 Vietnamese provinces. Our findings highlight the critical role of innovation maturity and institutional context in shaping intra- and inter-community diffusion processes. In the U.S., early understandings of EA led to a focus on know-what and know-why with a generic and diverse know-how discourse. In Vietnam, matured understanding of EA led to a dominant know-how discourse that focused on a specific use-case. Additionally, U.S. decentralized governance enabled a leader-driven approach with blending theorization and half-haphazard translation, while Vietnam’s centralized governance favored an artifact-driven approach with imitated theorization and disciplined translation. By integrating innovation maturity and institutional context in the analyses, this study offers nuanced insights into the diffusion of complex IS innovations across organizational communities.
