System Dynamics Review Research Articles

Minding the abstraction gap: approaches supporting implementation

AbstractRegardless of insights gained from building and analyzing dynamic models, the only strategies people can act on are those in their heads. The strategies people internalize are related to their perceived capacities to act—the verbs they believe they can do. If we want others to implement model‐informed policies, then we must connect model abstractions with new situated, concrete actions stakeholders can take. We can emphasize opportunities to act with SD representations, navigating levels of abstraction cleanly, identifying flows as verbs, and choosing variable names that signal who is acting. By drawing on social‐science theories as we offer our grammar of accumulations, activities, and relationships in the language of actions accessible to stakeholders, we help connect experiential understandings to richer, dynamic explanations people can internalize and so discover situated steps to implement policies informed by modeling. © 2024 The Author(s). System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Developing theoretically grounded causal maps to examine and improve policy narratives about global challenges

AbstractThe Sustainable Development Goals present a call to action for all countries to accelerate the implementation of solutions to address the world's biggest challenges. While policy portfolios to achieve such goals should be varied, often dominant policy narratives cluster around limited themes. We use a grounded theory approach to elicit causality from qualitative data to visualize interactions across variables spanning multiple domains influencing global challenges. We develop a comprehensive causal loop diagram, where we assess the impact of dominant policy narratives and expand the formulation of policy options. Our approach serves as an exemplar application of qualitative system dynamics to distill the operational logic of policy narratives that can subsequently be considered in model‐based policy analysis. We illustrate our approach by focusing on the interactions among poverty and hunger and compare policy implications arising from the dominant narratives only versus those arising from a more comprehensive understanding of the interactions. © 2024 The Author(s). System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Using system dynamics to support a functional exercise for pandemic preparedness and response

AbstractIn pandemic preparedness and response, a Functional Exercise (FX) is used to simulate a situation as close to a real‐life event as possible without the deployment of resources. Participants are drawn from public health emergency operations centres, and work through a scenario script to test possible responses to a novel pathogen outbreak. This paper summarises the role of system dynamics modelling in the design and implementation of a functional exercise, which involved the Dutch and German national public health institutes in March 2023. The findings confirm the value of the system dynamics method in integrating disease and hospital models, and also highlights how well the method aligns with modern software development processes. The paper concludes with a discussion of what worked well, and presents areas for future enhancements of management flight simulators to support functional exercises. © 2024 The Author(s). System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

From text to map: a system dynamics bot for constructing causal loop diagrams

AbstractWe introduce and test the System Dynamics Bot, a computer program leveraging a large language model to automate the creation of causal loop diagrams from textual data. To evaluate its performance, we ensembled two distinct databases. The first dataset includes 20 causal loop diagrams and associated texts sourced from the system dynamics literature. The second dataset comprises responses from 30 participants to a vignette, along with causal loop diagrams coded by three system dynamics modelers. The bot uses textual data and successfully identifies approximately 60% of the links between variables and feedback loops in both datasets. This article outlines our approach, provides examples, and presents evaluation results. We discuss encountered challenges and implemented solutions in developing the System Dynamics Bot. The bot can facilitate extracting mental models from textual data and improve model‐building processes. Moreover, the two datasets can serve as a test‐bed for similar programs. © 2024 The Author(s). System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Are we there yet? Saturation analysis as a foundation for confidence in system dynamics modeling, applied to a conceptualization process using qualitative data

AbstractSaturation is a useful concept for system dynamics, yet it has not been widely explored or integrated into the modeling process. In this article, we describe saturation as a metaphor describing the point at which a conceptual representation of a system meets the study purpose and no longer requires modification. When saturation is reached, additional data about the problem would not offer added information, thus indicating that additional data gathering and analysis would likely be redundant. We discuss two visualization techniques, “saturation curves” and “shared understanding diagrams,” for assessing saturation when conceptualizing with causal loop diagrams and show their application in a case example. Using saturation analysis during a system dynamics research process has many advantages, including: (i) identifying model structures potentially needing revisions, (ii) observing the extent to which evidence supports the current conceptualization, (iii) reflecting extensively, (iv) documenting important modeling decisions, and (v) potentially improving the problem statement. © 2024 The Author(s). System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

From text to model: Leveraging natural language processing for system dynamics model development

AbstractTextual data is abundantly available, and natural language processing (NLP) facilitates its analysis. However, system dynamics (SD) modelling relies on the modeller to identify relevant information. We explore the ability of NLP models to support SD modelling by identifying causal sentences in texts. We provide a primer on the notion of causality in SD and on the linguistic properties of causality, followed by an introduction of NLP models suitable for this task. Using three test cases, we evaluate the performance of the NLP models using common evaluation metrics and an SD model completeness metric. We conclude that NLP models can add considerable value to SD modelling, provided that remaining challenges are addressed. One such caveat is the difference we observe between information regarded as causal and information relevant for describing system structure. We discuss how these challenges can be addressed through collaboration between the NLP and SD fields. © 2024 The Author(s). System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Preparing for pandemic response in the context of limited resources

AbstractPandemics are outbreaks of an infectious disease that increase morbidity and mortality over a wide geographic area. These events require large‐scale interventions from governments and health agencies to curtail transmission within a population. In assessing the impact of these interventions, policymakers avail themselves of simulations from compartmental models. However, it is commonplace that modellers employ fixed fractions to represent interventions, which implicitly assume that resources instantaneously and boundlessly adjust to the desired target and may predict overly optimistic outcomes. Here, we propose a model that integrates four crucial countermeasures subject to resource constraints. We present this structure utilising the concept of small models and frame the simulations in the context of a hypothetical spread of influenza in the Netherlands, drawing on empirical data. After incorporating resource constraints, we find that only a comprehensive response controls the disease. These findings highlight the need for improving strategic plans to support pandemic preparedness. © 2024 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Developing model‐based storytelling to share systemic insights to the public during the COVID‐19 pandemic

AbstractCommunicating dynamic insights to a wide audience constitutes a long‐standing challenge among system dynamics modelers. We propose that telling stories is a compelling way of introducing feedback insights, as well as an understanding of how our individual decisions are linked to social behaviors in our day‐to‐day living. These decisions often involve moral and ethical trade‐offs. In this article, we use examples and heuristics to illustrate how the process of building a system dynamics model can drive a storytelling project. In a complimentary manner, the process of storytelling supports and enriches a model building project by exploring new dynamic hypotheses. © 2024 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

A framework for using Theory of Constraints thinking processes and tools to complement qualitative system dynamics modelling

AbstractWhile the tools currently used for qualitative system dynamics (Qual SD) modelling are very powerful in providing a holistic perspective and a framework for understanding complexity and change, they are often not explicitly designed to build and implement long‐term solutions based on that understanding. The Theory of Constraints (TOC) thinking processes and tools focus on these important aspects of the decision‐making process. We provide a six‐stage framework combining selected tools from TOC's thinking process and Qual SD's modelling process to provide a more rigorous systems thinking change process. We illustrate the methods and component tools via a case study on a complex societal issue (sale of alcohol in New Zealand supermarkets) developed for teaching purposes. We demonstrate the value of the framework, highlighting complementarities between tools, and show how specific insights emerged using each of the tools, with more insights resulting from using Qual SD and TOC collectively than separately. © 2024 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

History of the Beer Game

AbstractThis article describes the history of the Beer Game. By triangulating information from literature, archival analysis, and interviews with experts in the field, the main changes in the game over its almost 70‐year history are identified. The article discusses three aspects of the game: 1) its structure (phases of its history, stocks and flows, parameters, etc.); 2) the process for playing the game; and 3) the game debrief. The structure of the Beer Game, and the process for running it, have stabilized over the years into what is now a de facto standard approach. Additional work is needed in the game debrief, specifically in the clarification of key insights and messages (depending on the context of the use of the game), in how to communicate such messages to different audiences, and in the development of support materials for its delivery. © 2024 UChicago Argonne, LLC. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

What is (quantitative) system dynamics modeling? Defining characteristics and the opportunities they create

AbstractA clear definition of system dynamics modeling can provide shared understanding and clarify the impact of the field. We introduce a set of characteristics that define quantitative system dynamics, selected to capture core philosophy, describe theoretical and practical principles, and apply to historical work but be flexible enough to remain relevant as the field progresses. The defining characteristics are: (1) models are based on causal feedback structure, (2) accumulations and delays are foundational, (3) models are equation‐based, (4) concept of time is continuous, and (5) analysis focuses on feedback dynamics. We discuss the implications of these principles and use them to identify research opportunities in which the system dynamics field can advance. These research opportunities include causality, disaggregation, data science and AI, and contributing to scientific advancement. Progress in these areas has the potential to improve both the science and practice of system dynamics. © 2024 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Descriptive design structure matrices for improved system dynamics qualitative modeling

AbstractQualitative modeling approaches can be useful in system information collection, model analysis, and formal model development. This is difficult when the number of elements and their interactions in the system is large. System dynamicists need additional tools and methods to conceptually model these large tightly coupled systems. We propose and test the Descriptive Design Structure Matrix (DDSM) as a qualitative system dynamics modeling tool and approach for systems with many elements and more interactions that can reasonably be modeled individually using traditional system dynamics methods. A DDSM consists of four parallel and internally consistent matrices that describe system interactions with binary relations, nontechnical text, technical text, and literature support. By including and documenting system information in multiple forms, DDSMs facilitate multiple stages of system dynamics modeling, improve modeler communication with system participants and domain experts, and improve model rigor. DDSM construction is described. A case study of the 2014 flooding in Kashmir is used to illustrate and test a DDSM and its application. Due to their compact format, DDSMs provide a useful visual communication aid, intuitive reasoning tool, and foundation for formal system dynamics modeling and analysis. © 2024 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Techniques to enhance the public policy impact of qualitative system dynamics models

AbstractThis article demonstrates techniques to enhance the public policy impact of qualitative system dynamics models. We focus on the effective use of a large causal loop diagram (CLD) to explore a multifaceted problem situation. We discuss the conditions that can lead to developing a large CLD, the challenges this presents, and techniques that can be used to overcome them. Several techniques are discussed related to an online group model‐building (GMB) process, the use of quantitative data, visual model analyses using a software tool and reporting. The techniques are demonstrated using an impactful case study on the social impact of the COVID‐19 pandemic. We reflect on the efficacy of the approach through the lens of systems thinking and conclude that the techniques made a positive contribution to all aspects of systems thinking. Several avenues for future work are discussed. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Using causal loop diagrams to develop evaluative research propositions: opportunities and challenges in applications to nature‐based solutions

AbstractCausal loop diagrams (CLDs) are often used to provide an overview of important systemic elements related to an issue, rather than to inform empirical evaluations (studies which assess changes following an intervention using observed data). We suggest that empirical evaluations may benefit from the development of systems‐informed research propositions (specific testable causal assumptions with an emphasis on feedback loops) used to guide subsequent data collection, hypothesis testing and interpretation. We describe a qualitative systems‐thinking informed approach building on preexisting CLDs, published evidence, and expert/stakeholder consultation and reflect on our experience applying this to the early stages of two nature‐based solution (NBS) evaluations. We reflect on our experience and suggest that CLDs can be usefully employed to develop systems‐informed research propositions to inform subsequent empirical evaluation. This may lead to novel policy‐relevant research propositions which differ substantially from effectiveness‐oriented (“did it work?”) research questions. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Ethical considerations of using system dynamics in participatory settings: a social‐ecological‐systems perspective

AbstractThe social‐ecological systems (SES) approach elicits a broad understanding of some of the most pressing socionatural challenges (e.g. resource scarcity, biodiversity loss, and climate change) and the responsibility that humans have in addressing them. System dynamics has proven a powerful paradigm for dealing with complex SES‐related issues. Here we discuss some ethical considerations of using system dynamics (SD) to model SES, something that is often either overlooked or discussed as an isolated issue. Sustainable development and human rights are used as ethical standpoints across the modelling cycle, opening the discussion around guiding principles that need to be considered when modelling SES. Based on these, a set of guiding ethical questions are identified and classified across a participatory SD modelling cycle. This structured approach is a simple yet potentially useful tool for SD practitioners to examine the ethical implications of their modelling endeavours in the context of grand societal challenges. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Measuring the change in behavior of a system with a single metric

AbstractLoops that Matter (LTM) provides a practical and comprehensive way to understand which feedback loops are driving model behavior at different points in time. LTM describes from which loops the observed change in behavior across all stocks in the model originate. In this paper we present a method to measure the magnitude of the change in behavior of all stocks in the model based on net flow values, relative to the magnitude of change taking place across an entire observation (simulation) period. We call this new metric the “system change”. We then demonstrate how our system change metric can be visualized using loop scores to highlight those loops that are predominantly responsible for the changes in behavior exhibited by the model. This helps analysts focus in on the feedback loops that are prime candidates for interventions to change the model behavior. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Strengthening a weak link: transparency of causal loop diagrams — current state and recommendations

AbstractTransparency is a critical aspect of systems science. While transparency of quantitative models has been assessed, transparency of their qualitative structures has been less scrutinized. We assess the transparency of causal loop diagrams (CLDs), a key qualitative visualization tool in system dynamics. We evaluate System Dynamics Review (SDR) publications and a sample of most‐cited comparable articles in other journals. We assess the inclusion of a plain‐language methods statement, overall discernibility of the methods, and identification of causal link sources. Reviewing 72 articles (SDR: 36; other journals: 36), only 44%, 38%, and 25% fully satisfy each criterion, respectively. SDR articles are characterized by higher transparency in the clarity of CLD development method and communication of causal link sources, yet the potential for enhancement is evident. We provide specific recommendations to increase the transparency of CLDs. Transparent reporting benefits original research authors, future expansion of CLDs, and the systems science community. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Feedback dynamics of the low‐income rental housing market: exploring policy responses to COVID‐19

AbstractThe economic impact of COVID‐19 threatened mass housing insecurity undermining the health and financial recovery from the pandemic. Unprecedented federal policy responses halted court‐ordered evictions and injected billions of dollars in rental assistance, but questions remain whether housing interventions adequately accounted for dynamics that drive landlord‐tenant interactions, including accumulations of rental and mortgage arrears, rental unit availability, and low‐income housing options. A system dynamics model probes complex feedback dynamics driving tenant and landlord decision‐making in the low‐income rental housing market pre‐ and postpandemic protections. Feedback loops highlight trade‐offs considered by low‐income tenants and landlords in the context of scarcity and uncertainty. Simulations suggest the eviction moratorium and federal emergency rental assistance prevented a tidal wave of evictions, but rental arrears, overcrowding, and homelessness remain elevated. Failure to address underlying financial hardship and limited affordable housing undermines COVID recovery. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Dynamics of interdisciplinarity: a microlevel analysis of communication and facilitation in a group model‐building workshop

AbstractParticipatory system dynamics is assumed to generate inter‐ and transdisciplinary understanding and whole‐system perspectives via scripted workshop structure, facilitation, and the use of visual boundary objects. However, there is little research into how exactly workshop activities and facilitators affect communication dynamics during a workshop and create an interdisciplinary perspective. Thus, we offer an innovative dynamic understanding via a rare microlevel analysis of facilitation and dynamics of communication and interdisciplinarity in a group model‐building workshop. We investigate how the conversation focus unfolds over time and examine in depth disciplinary transitions as well as the facilitator's role. We also analyse participants' perceptions of interdisciplinarity from the workshop and provide a research framework for workshop microlevel analysis. Based on the workshop's heritage science setting, we discuss the recursive nature of generating joint meaning and the use of participatory system dynamics for managing interdisciplinarity in a research project and make recommendations. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

Constructing causal loop diagrams from large interview data sets

Abstract“Tackling the Root Causes Upstream of Unhealth Urban Development” is a trans‐disciplinary research project seeking to map and understand urban development decision‐making, visualise stakeholder mental models and codevelop improvement interventions. The project's primary data was gathered through 123 semistructured interviews. This article applies, compares, and discusses four variations on a method for constructing causal loop diagrams to illuminate mental models and collective decision‐making, based on manual and semiautomated processes applied to individual interview transcripts and datasets collected by thematic analysis. It concludes that while semiautomated approaches offer some time saving over manual approaches when applied to large data sets, care is required in interpreting and including peripheral contextual variables at the boundaries of the thematic analysis. Decisions regarding automation depend on the purpose of the modelling. Finally, the article recommends future applications record quantitative descriptors characterising the process of constructing CLDs from large qualitative data sets. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.