From complexity to parsimony: A systems thinking validation of the multiple streams framework in abortion policy...

Abortion policy is a highly contested area of health policy. Despite international recognition of abortion as a human right, legal restrictions persist in many countries, and recent decades have seen both liberalization and retrenchment of abortion laws. While much research has examined the politics and outcomes of abortion policy reform, less attention has been paid to the upstream process of how abortion emerges on the policy agenda. This study addresses this gap by focusing on agenda setting for abortion policy, using Kingdon's multiple streams framework (MSF) and systems thinking.

This exploratory study integrates MSF with systems thinking and causal loop diagramming to map the dynamic interactions among government characteristics, policy communities, policy-maker attributes and external events. A purposive review of 19 key works from the MSF literature was conducted, selected for their theoretical contributions and detailed descriptions of stream interactions. Qualitative text coding and quotation analysis were used to identify causal relationships, which were then aggregated into a causal loop diagram. Model validation focused on micro-structure elements, and the framework was tested against two case studies: Ireland and Nicaragua.

Analysis yielded 167 unique elements and 338 causal links, distilled into 81 key variables. The causal loop diagram demonstrates that convergence of the problem, policy and politics streams is shaped by reinforcing and balancing feedbacks, rather than random chance. Key factors influencing agenda setting include party institutionalization, policy entrepreneur effectiveness, social inequality and the gravity of focusing events. The case studies illustrate how variations in political institutions, mobilization efforts and external events can lead to divergent policy trajectories.

This study provides theoretical validation that the parsimonious MSF can account for the complexity of abortion policy agenda setting when integrated with systems thinking. The causal loop diagram identifies actionable leverage points for advocacy and policy reform and offers a dynamic, testable model for understanding agenda setting in contentious policy domains. These findings bridge theoretical innovation with practical relevance, laying a foundation for future empirical research and offering insights for scholars, advocates and decision-makers seeking to influence the policy agenda for abortion and other complex health issues.