Policy formulation

Who determines policy formulation? Who participates in policy formulation? Explain why problem definition is important in the policy formulation process. Who are policy entrepreneurs and what is their role in problem definition?
What are top-down models of policy formulation and how do they differ from the bottom-up model? What is the technical difference between the rational comprehensive model and the incremental model of policy formulation? Explain the strengths and weaknesses of each model in the policy formulation process.
What is the target population model? How does it differ from the conventional conception of policy formulation?
Who are street-level bureaucrats? What are street-level bureaucracies? I low do street-level bureaucrats make public policy?