Studies of policy change have advanced to the point where the basic contours and factors driving policy sequences are now reasonably well identified and understood with a great deal of empirical evidence pointing to the prevalence of punctuated equilibrium processes in many policy fields. However the reasons why such processes occur is less well understood. Most attention to date has focused upon homeostatic models in which exogenously-driven shocks undermine institutionally entrenched policy equilibria. This article addresses the difficulties this account faces and the conceptual challenges which must be overcome to provide a solid grounding for the understanding and analysis of long-term policy dynamics. It focuses on the merits and demerits of alternative explanations featuring either random junctures and ‘positive-return’ sequences – path dependency – or embedded junctures and ‘reactive’ sequences – process sequencing. Models of policy-making over time using the latter two concepts, it is argued, are more likely to account for the large majority of policy dynamic than the former.
