Agenda success requires three independently necessary streams to converge at once.

Evidence

John Kingdon’s (1984) famous work on agenda setting illustrates other features of substitutability and the two-level model. Kingdon reformulated the garbage can model into one with three “streams”—problem, solution, and political context—which are individually necessary and jointly sufficient for agenda success. He emphasized how contingent and nonlinear the process is by which these three factors occur at the same time. He also stressed substitutability in the various ways in which the three streams can be filled. — Gary Goertz, Social Science Concepts and Measurement, 1519

Categorization

• SEED: Angle: ‘The architecture of timing’ — why policy windows, not good ideas, decide which problems get solved, tying Kingdon’s streams to modern policy failures.