Policydiffusion

Policydiffusion is the study of how policy innovations spread across political jurisdictions, organizations, or other actors. It examines the patterns by which ideas, instruments, or programs adopted in one setting become adopted or considered in others. Diffusion can occur horizontally between similar jurisdictions such as states or cities, vertically across levels of government, or across organizational and international boundaries.

Diffusion processes arise through several mechanisms. Learning and imitation occur when jurisdictions observe outcomes and replicate successful approaches. Competition can drive adoption as governments seek to align with rivals or attract resources. Coercive diffusion operates through conditional funding, mandates, or other forms of external pressure. Normative diffusion reflects the influence of professional norms, epistemic communities, or international best practices. Diffusion is shaped by factors such as problem salience, perceived policy effectiveness, compatibility with existing institutions, and the strength of policy networks and entrepreneurs who promote adoption.

Researchers study policydiffusion with a range of methods, including event history analysis, diffusion models, network analysis, and comparative case studies. Data sources often include legislative records, policy databases, implementation reports, and international or intergovernmental communications. Outcomes of interest include time to adoption, the sequence of adoptions, and variations in policy design across jurisdictions.

Limitations include distinguishing diffusion from independent invention or borrowing for other reasons, accounting for endogeneity, and addressing contextual differences across settings. Policydiffusion remains closely related to concepts such as policy transfer, adaptation, and learning, but it emphasizes the mechanisms and patterns by which policies spread.