Moving Beyond Third Generation Policy Implementation Research Towards a Fourth Generation: Synthesizing Across Policy Process Theories

ABSTRACT Policy implementation research has progressed significantly in line with the third generation paradigm, particularly regarding methodological diversity and research design. However, the anticipated theoretical convergence has not materialized. This article explores how the Multiple Streams Framework (MSF), a leading policy process theory, could support this theoretical development. We first discuss empirical trends in policy implementation research, drawing on a literature review to summarize research design, methods, and theory. With this background, we then compare key empirical and conceptual features using two literature reviews of MSF and our implementation review. We argue that they are complementary in important respects and can be mutually beneficial. Implementation offers empirical and methodological robustness, which can further develop MSF, while MSF offers a unifying conceptual structure that could help situate implementation more clearly within the policy cycle. Such theoretical synthesis could be a next step towards a fourth generation contingency theory of implementation research.