Although these attributes of innovations have been extensively studied, others have been examined and proposed to help explain the uptake of complex innovations in organizations or other settings (Greenhalgh and others, 2004). These include the notion of fuzzy boundaries, where the distinction is made between the "hard core" (or irreducible elements) of a complex, multicomponent innovation and the "soft periphery," which includes the organizational structures and delivery systems required for full implementation. Elements of this concept clearly link with Rogers's (2003; concept of reinvention .