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

Alvarado Health Research Policy and Systems https://doi.org/10.1186/s12961-025-01392-y (2025) 23:143 Health Research Policy and Systems Open Access RESEARCH From complexity to parsimony: A systems thinking validation of the multiple streams framework in abortion policy agenda setting Gabriela Alvarado1* Abstract Background 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. Methods 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. Results 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. Conclusions 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. *Correspondence: Gabriela Alvarado 1 RAND Corporation, 1200 South Hayes St, Arlington, VA 22202‑5050, USA Background Abortion is a highly contested area of health policy given the complex interplay of religion, culture, public health, human rights and social equity. Despite the recognition of access to abortion as a human right in numerous international conventions and treaties, legal restrictions © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Alvarado Health Research Policy and Systems (2025) 23:143 to abortion persist in many countries around the world [1]. For most of the nineteenth and the first half of the twentieth century abortion was illegal in most countries; however, in recent decades countries across the globe have experienced both liberalization and retrenchment of abortion laws [2, 3]. Understanding not only why abortion policy reform occurs but how abortion even gets on to the policy agenda is a challenge for researchers, advocates and policy-makers. A substantial body of literature across numerous academic disciplines have examined the politics of abortion at the country level, including the roles of religious institutions, social movements, political parties and international influences in shaping abortion policy reform [3–5]. Nonetheless, the focus of these studies is often centred around the content of policy debates, the outcomes of judicial and legislative processes or the public health impact of increased access to abortion, rather than the upstream question of how abortion can emerge as an issue that is thought to require a policy action in the first place. This study addresses this gap by focusing specifically on the process of agenda setting for abortion policy. Fig. 1 Kingdon’s multiple streams framework [9] Page 2 of 18 Theories of agenda setting are fitting in this situation, as they aim to articulate why some issues rise to the forefront and capture the attention of the public and policymakers, while others are forgotten [6, 7]. One useful theoretical framework to contextualize agenda setting was described by John Kingdon in 1984 [8]. Kingdon’s multiple streams framework (MSF) proposes that there are three parallel streams – problems, politics and policy – and when these three streams come together, a “window of opportunity” is created where the timing is optimal for placing the issue on the policy agenda (Fig. 1 [9]). The problem stream refers to the goal gap – meaning the difference we can observe between the current state and the desired state. However, there is no universal problem definition, and many people may have different perceptions and definitions for the same problem. The policy stream represents the universe of possible solutions and alternatives to address the problem. Lastly, the politics stream refers to the mood of the people and whether the public and/or elected officials care about the problem as stated. When the three streams come together, this window of opportunity represents an optimal timing of issue placement Alvarado Health Research Policy and Systems (2025) 23:143 on the policy agenda which can increase likelihood of a targeted action and thus a favourable policy outcome. For abortion policy reform, where the path to change is rarely linear, the MSF provides a helpful approach to examine the conditions (...truncated)