In a political climate characterized by uncertainty, institutional constraints, and abundant information, how do we understand policy change as a part of a dynamic policy process? For years, scholars described the process as incremental shifts interrupted by elections, and highlighted the way rational actors try to maximize preferences. The data on policy making showed this to be too narrow an approach, as most punctuations in policy do not correlate with changes wrought by elections. Baumgartner and Jones developed a theory to explain a more complex policy process by reassessing information processing, emphasizing the principles of bounded rationality and the limited attention of actors and institutions. Punctuated Equilibrium Theory describes that less predictable policy process; one which is characterized by long periods of stability with incremental changes, interrupted by episodic changes that may be externally or internally initiated. The key to the process lies in the disproportionate information processing that causes policy makers of all sorts to ignore important signals of problems for long periods before taking action. PET emerged out of a need to understand the agenda-setting stage of the political process, but it has evolved beyond its agenda setting origins to explain underlying components of change throughout the policy process.