Coupling

A key part of the Multiple Streams Approach involves the ‘coupling’ of streams, by policy entrepreneurs (who might do this by exploiting focusing events, or successful reframing of existing circumstances).

Two excellent quotes on

Coupling is perhaps the most important aspect of a multiple streams model, yet it is one of the least understood and explored in the literature.  The original garbage can model simulation was criticized for being devoid of the human element because it assumed this coupling is strictly a function of energy levels brought into the decision (Bendore, Moe, and Shott, 2001; Masuch and LaPotin 1989). Kingdon eschewed [sic] the criticism by stressing the importance of entrepreneurs – who may not be policymakers themselves – in the coupling process….
(Zaharadias, 2003:139)

and

… there are two coupling modes depending on whether the policy window opens in the problem or politics stream. Windows that open in the problem stream encourage consequential coupling (finding a solution to a given problem). Policymakers, first identify a problem and then search in the solution space for the appropriate solution. This is the way most studies assume that policy is made. The multiple streams approach, however, suggests that policy can be made by solutions chasing problems to which they can be attached. Policymakers first identify pet policies, which they try to enact irrespective of the problem they may solve. When windows open in the politics stream, coupling is likely to be doctrinal (finding a problem to a given solution). Doctrinal coupling implies that the ideology of the ruling party rather than the problem itself guides the selection of solutions.
(Zaharadias, 2003:139)

Zaharadias, N. 2003. Ambiguity and Choice in Public Policy: Political Decision Making in Modern Democracies. Washington, D.C: Georgetown University Press.