ELKINS, Zachary <br/><br/>
On waves clusters, and diffusion :  a conceptual framework 

 - Thousand Oaks :  SAGE,  March 2005 
<br/><br/> This article makes a conceptual and theoretical contribution to the study of diffusion. The authors suggest that the concept of diffusion be reserved for process (not outcomes) characterized by a certain uncoordinated interdependence. Theoretically, the autors identify the principal sources of clustered policy reforms. They then clarify the caracteristics specific to diffusion mechanisms and introduce a categorization of such processes. In particular, they make a distinction between two types of diffusion: adaptation and learning. They argue that this categorization adds conceptual clarity and distinguishes mechanisms with distinct substantive  consequences