Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Search in posts
Search in pages

Go Home

Achieving a Polio-Free World Through System Dynamics Simulation

EXECUTIVE Summary

This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to fund the polio eradication effort.

The model made a case for continued funding policy eradication by providing compelling evidence that polio outbreaks will cost more than continued intense vaccination. While the reduction in the incidence of cases was making it look like the cost of immunization was exceeding its benefits, this application of System Dynamics shows that dealing with ongoing, long-term sporadic outbreaks resulting from stopping or slowing down immunization programs is even more costly than dealing with sporadic outbreaks.  The process resulted in a simulation model that estimates the costs of two alternative policies. Option 1 was to continue efforts to eradicate polio and option 2 was to reduce the immunization rate and deal with sporadic outbreaks.

This analysis came at a critical time. In February 2007, the WHO Director-General, Dr. Margaret Chan, convened an urgent stakeholder consultation to discuss the option of switching from eradication to control. Clearly showing the dynamics and giving the wavering commitment a name helped key stakeholders appreciate the options quantitatively and with a much longer time horizon. Since then, efforts have continued to focus on finding the resources needed for complete eradication and on dealing with the other complex challenges that remain. With the support of the simulation model, national and global health leaders and financial supporters re-committed to completing eradication, which led to several hundreds of millions of dollars of resources.

#Polio #WHO #Vaccination #Health

The Problem

Following the successful eradication of smallpox and impressive progress in the elimination of polio in the Americas, in 1988 the World Health Assembly committed to the global eradication of wild polioviruses by the year 2000. By 2000, the Global Polio Eradication Initiative (GPEI) had significantly reduced the global circulation of wild polioviruses. However, in 2002–3, faced with insufficient funding to continue intense vaccination everywhere, the GPEI focused its vaccination efforts. At the time, wild polioviruses continued to circulate in six countries, but many other countries remained vulnerable to importation. Political and logistical challenges led to outbreaks and exportations, and between 2004 and 2006 wild polioviruses appeared again in previously polio-free African and Asian countries.

Toward the end of 2005, a debate began about abandoning the goal of eradication. How could the world continue to justify the significant use of resources (both financial and human) on polio, particularly with the number of cases globally already so low and so many other disease control and health services programs in need of resources?

The Solution

The dynamic disease outbreak model represents a more complicated version of the standard SIR model used in a popular System Dynamics textbook (Sterman, 2000). However, in Polio, we must deal with different types of imperfect immunity (i.e., from historic or recent exposure to polioviruses – including the oral poliovirus vaccine and/or vaccination with the inactivated poliovirus vaccine – as well as a latent period and routine or supplemental immunization rates). Modifying and expanding our existing model allowed us to determine that it was not possible to “effectively control” (i.e., achieve low cases) at a low cost. This means that control either implies high costs and low cases, or low costs and high cases, but not low costs and low cases.

Stock an Flow Diagram

However, our most significant insight came from exploring the dynamics of the economic investment in eradication. After watching the GPEI deal with the reintroductions of wild polioviruses in previously polio-free countries between 2004 and 2006, we recognized that reducing vaccination led the stock of susceptible individuals to build up and ultimately to outbreaks after some delay. Responding to the outbreaks requires reinvesting in intensive vaccination, which after some delay contains the outbreak and reduces or eliminates the circulation of the virus. With success comes a perception that the high level of investment compared to the low incidence is no longer justified. If policymakers succumb to the resulting pressure to reduce vaccination spending, this creates a situation in which populations again become vulnerable to new outbreaks.

“If policymakers succumb to the resulting pressure to reduce vaccination spending, this creates a situation in which populations again become vulnerable to new outbreaks.”

To capture this behavior, we constructed the negative feedback loop shown here, which we called  “wavering”. We incorporated this feedback loop into our dynamic disease model and tailored the model to two populous northern Indian states in which wild poliovirus still circulates. We explored two options: (1) vaccinate intensively until eradication;  and (2) vaccinate intensively only if the costs per incident case remain below a certain acceptable level, but reduce the vaccination intensity otherwise  (i.e.,  a “control” option with the possibility of wavering).

Causal Loop Diagram Polio
Simulation Chart Polio

Outcomes

This application of System Dynamics highlights the systemic causes of overruns and emphasizes the importance of understanding the complex physical and social systems within which large projects operate. We, fortunately, saw the wavering commitment loop when no one else seemed to see it, and we went beyond just seeing the loop to build and use a model that provided answers to critical questions at the time the decision makers could use them (and needed them and asked us). In the presentation to the stakeholders, we showed the results to tell the dynamic story in the simplest possible way (i.e., by comparing a firm commitment to a wavering commitment showing the cumulative costs and cases).

We did not focus on explaining the model itself to attempt to walk the decision makers through the equations or diagrams. Instead, we focused on communicating the key insights based on what they already knew (e.g., the 2002–3 reduction in vaccination led to big outbreaks and high costs). However, we anticipated and received (as anticipated) some criticism from economists who did not recognize in the model a traditional health economic analysis, but these were relatively limited.

OTHER SUCCESSFUL APPLICATIONS

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Upcoming Events

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Join us

LET US BE PART OF YOUR JOURNEY

Do you want to lead your organization into the future by overcoming paradigms and creating change? With Systems Thinking and System Dynamics you will enable powerful decision-making and find the leverage points to improve profits, strategy, efficiency, sustainability, and more.

Rebecca Niles

Talk with Us

The most efficient way to align your needs with our offerings is to schedule a meeting with our Executive Director, Rebecca Niles

Engage a Systems Consultant

Looking for a Systems Consultant? Fill out this form and we will follow up with a call and, soon enough, the right person for the job.

Experience Systems Thinking

Bring in a facilitator to unleash the power of Systems Thinking in your organization. Fill out this form for a Beer Game facilitator and join the companies, and graduate and MBA programs that play this game all over the world. Contact us if a facilitator for a different game is needed.

WPI System Dynamics Fundamentals micro-course 1

Start Learning

Join the WPI Sytem Dynamics Fundamentals Course to understand the causes of dynamic behavior at a basiic level and much more! The course is self-led and self-paced.

System Dynamics Helps Reduce Waiting Lines for NHS Patients

EXECUTIVE Summary

The impact of COVID-19 on the National Health Service (NHS) in England, led to growing record waiting lists, deterioration of patients and recovery of elective care became the number one priority.

Creative solutions were needed to tackle the elective recovery backlog, however, the health service in Norfolk and Waveney in the East of England were constrained by limited resources. System Dynamics allowed operational and clinical staff to test the impact of major interventions, aiding decisions for leaders in the system about where best to allocate resources and transform services to benefit patients and reduce waiting times.

The modelling exercise explored ways to address backlogs in the Musculoskeletal pathway with the aim of returning them to sustainable levels while providing good outcomes for patients. The insights provided by the model considered not only capacity restrictions but also the final outcomes for patients.

The model starts from the population and incidence of activity, and through the community (including GP referrals, diagnostics, community physiotherapy), before then moving through into secondary care. Moving into secondary care it covers first appointment, follow up, waiting lists, beds, and incorporates how trauma impacts on elective waiting lists while considering constraints in theatres capacity and community services.

#England #NHS #Health #Waiting lists #Musculoskeletal

The Problem

Integrated care systems (ICSs) are partnerships of organisations that come together to plan and deliver joined up health and care services, and to improve the lives of people who live and work in their area. Norfolk and Waveney Integrated Care System (ICS) in England had a number of challenges across the health system which comprises three acute hospitals, two community providers, and a mental health trust. Prior to COVID-19, elective care across Norfolk and Waveney ICS was already seeing increases in waiting lists and it was not meeting national standards with some patients waiting over 52 weeks for planned care. COVID-19 then saw the postponement of the elective care which further impacted the situation negatively, leading to one of the biggest cohorts of 104 week waits in England. 

To tackle the challenges across the whole system, clinical and non-clinical colleagues came together with the support of NHS England and Whole Systems Partnership, to develop three System Dynamics models in Stella Architect starting with the Trauma and Orthopaedics speciality within the Musculoskeletal (MSK) pathway and then also models for the Dermatology and Eye Care pathways. The models were used to test different scenarios and identify how healthcare operational interventions designed to reduce the elective care backlog impact patients across the Norfolk & Waveney ICS system.

The Solution

For the MSK pathway model, a group of analysts across the system first engaged with clinical and operational colleagues in stakeholder workshops identifying the key issue, exploring what-if questions, and developing a high-level conceptualisation of the model.

The model was developed using a modular approach by building separate parts of it first and then bringing the various components together. A user interface was created to support operational colleagues to understand the outputs of the model and enable decision-making. Operational colleagues used the interface to interactively adjust variables such as expected demand and see impact projections on capacity and waiting lists.

The model was able to test the following ‘what if’ scenarios:

What if…

 …we provided open access to early self-referral and self-management including advice on holistic/lifestyle choices to improve ultimate outcomes and minimize the impact of delays caused directly or indirectly by the COVID epidemic?

…we deployed a multi-disciplinary team Advanced Clinical Practitioners (ACP) to triage long-wait patients and fast track those in greatest need, possibly to other providers, facilitating this with integrated IT systems?

…we eliminated interruptions to the capacity and therefore flow along the elective pathway from trauma or unscheduled care requirements, i.e. protected capacity?

MSK diagram 1

Once the high level model conceptualisation was agreed upon, a prototype model was developed by analysts across the system, who had begun to receive technical training in using the software. Analysts from across the system each took a different part of the system to model and once these were completed, the different parts were brought together to create the complete system model. The stock and flow diagram below shows main components in the model. Please note that the actual model is more complex than the one illustrated in the diagram.

SFD MSK

The user interface was accessible through a link on the internet, which allowed password holders to use and run the model.

Outcomes

There were many significant benefits and impact for doing this work including enabling high quality operational decision making around the elective recovery. This work helped to develop cohesion within the ICS, improving working relationships between analysts, clinicians, and operational staff across all of the stakeholders in the region.

 Here are some highlighted benefits and impact of creating a system model in Norfolk and Waveney:

> Different impacts of scenarios could be understood and visualised through the model

> End users are now testing their own what-if questions, and understanding how changes to parts of the pathway will impact other parts of the system

> An iterative process captured a multiplicity of voices with real life experiences of the service

> This project complemented existing quality improvement and elective recovery work happening in Norfolk and Waveney ICS

> Staff shifted from silo working to genuine system working

> More conversations are now happening about the harmonisations or pathways, the locations of diagnostic assessment centres and community hubs.

> This approach is empowering discussions with Integrated Care Boards at a system level

> Analysts are now equipped with technical skills in order to conduct system modelling

> Analysts have developed much closer relationships with clinicians.

Do you want to know more?

Model
Please note that this is an example model, it is not validated and it does not contain genuine data – it should be used to understand what the tool looks like and should not be used operationally.

Connect with Vanessa Perez Perez

OTHER SUCCESSFUL APPLICATIONS

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Upcoming Events

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Join us

LET US BE PART OF YOUR JOURNEY

Do you want to lead your organization into the future by overcoming paradigms and creating change? With Systems Thinking and System Dynamics you will enable powerful decision-making and find the leverage points to improve profits, strategy, efficiency, sustainability, and more.

Rebecca Niles

Talk with Us

The most efficient way to align your needs with our offerings is to schedule a meeting with our Executive Director, Rebecca Niles

Engage a Systems Consultant

Looking for a Systems Consultant? Fill out this form and we will follow up with a call and, soon enough, the right person for the job.

Experience Systems Thinking

Bring in a facilitator to unleash the power of Systems Thinking in your organization. Fill out this form for a Beer Game facilitator and join the companies, and graduate and MBA programs that play this game all over the world. Contact us if a facilitator for a different game is needed.

WPI System Dynamics Fundamentals micro-course 1

Start Learning

Join the WPI Sytem Dynamics Fundamentals Course to understand the causes of dynamic behavior at a basiic level and much more! The course is self-led and self-paced.

Using System Dynamics to Teach and Learn about COVID-19

Using System Dynamics to Teach and Learn about COVID-19

This Webinar is free due to the generous contribution of the University at Albany and California State University, Chico

A distinguished team of panelists demonstrated how we can all think globally and act locally on the most challenging topics of the day. From David Anderson’s discussion of work that has been ongoing since the onset of Covid to Babak Bahaddin’s pointing us to the latest diaries at the New Fadam farm site (needs website reference), the entire webinar is packed with insight.

By showing how cross-discipline expertise and international exchange of ideas and experiences can come together in a system dynamics initiative, this panel has placed the impacts of Covid at the center of their work.  We all know how the pandemic has influenced our lives, and this team is looking into why that happened and how to lessen its impact on us going forward.

Using a model developed by Ali Mashayekhi and applied extensively by Daniel Gordon, a component-based study and survey tool for COVID has been refined over the course of the COVID era. Luis Lunar-Reyes has applied the model to its effects on business and governmental response and Hyunjung Kim has taken the model and developed a self-study learning tool kit that is available under a Creative Commons license.

There is so much great work going on, watching this video can inspire System Dynamics specialists, and researchers from all disciplines, to take a look at Covid-19 through the lens of this model.

Ali N. Mashayekhi is a retired professor of management from the Sharif University of Technology in Tehran, Iran where he taught System Dynamics and strategic management. He received his BSc in Mechanical Engineering from Sharif University and his Ph.D. in System Dynamics from MIT in Cambridge Massachusetts.

Babak Bahaddin works as an associate consultant at isee systems. Babak holds a bachelor’s degree in engineering from Sharif University of Technology, and a Ph.D. in Information Science, from the University at Albany, State University of New York.

Daniel Gordon trained in System Dynamics at Rockefeller College, the State University of New York at Albany. He is retired from the New York State Health Department, where he spent 34 years working in health care policy analysis and HIV epidemiology.

David Andersen is Professor Emeritus in Public Administration and Information Science at the University at Albany – SUNY. He is a former President and Vice President for Finance for the System Dynamics Society as well as a winner of the Forrester Award.

Hyunjung Kim is a professor of management at California State University, Chico. She teaches strategy and management courses using system dynamics. She received her Ph.D. in Public Administration from the Rockefeller College of Public Affairs and Policy, University at Albany.

Luis Felipe Luna-Reyesis a Professor of Public Administration and Policy at the University at Albany and a National Academy of Public Administration Fellow. His research is at the intersection of Public Administration, Information Systems, and Systems Sciences.

Present at the Seminar Series

The Society Seminar Series consists of periodic online meetings on topics of interest to the systems thinking and System Dynamics communities. These virtual activities cover a wide range of topics that cross many domains while bringing together academics, practitioners, and students together for learning and lively discussion. Send your seminar proposal here

Sponsor a Seminar

The Society is actively looking for Seminar sponsors. This allows making a seminar open to all and free of charge. If your organization would like to sponsor one of these events, where you can promote your organization, firm or software, for instance, contact us at office@systemdynamics.org

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us

New Horizons of Systems Science

New Horizons of Systems Science

This Seminar was sponsored by the International Council on Systems Engineering (INCOSE).

Systems theory is developing to include new perspectives with a focus on integrated and inclusive transdisciplinary system approaches. This panel discusses new advances in systems science including critical systems thinking, social/socio-technical systems, and complex systems, which come together in the systems engineering principles. They also discuss where Systems Dynamics fits into this picture as well as other types of systems models.

By providing three perspectives on the discipline of Systems Engineering, the panelists shared a wide range of insights and experiences.  What the perspectives shared were ways Systems Engineering practitioners and the System Dynamics community could work together going forward.  One key to making New Horizons for System Science become reality is to merge the insights and experiences of each group into a shared, and sharable, practice.

 The relationship between Systems Science, Systems Thinking, and Systems Engineering is a key to understanding the range of applicable solution patterns

Erika Palmer began with the hope that both organizations, INCOSE and the System Dynamics Society, would continue to engage, learn, and innovate as part of a worldwide collaboration. The goal of the INCOSE panel is to foster an inclusive dialog on Systems Science. The purpose of the dialog is to accelerate the exchange and adoption of tools, techniques, and theories between the two sets of practitioners.

Michael Watson shared with the attendees that the upcoming release of System Engineering Principles will include Sociology as a topic.  By setting out the fifteen principles of Systems Engineering concisely, System Dynamics solutions can be applied to the principles.  Common patterns used across domains or across principles will provide leverage for other contributors.

Javier Calvo-Amodo shared insights from the perspective of building Systems Science disciplines and that students can participate with journal articles. Since System Dynamics provides a specific lens through which to view models, it can be used to validate the findings of other modeling types or to provide insights into what other modeling systems might reveal. A Systems Science map using Randomness and Complexity as the axes provided a guide to where specific System Dynamics developments can be best applied.

Erika Palmer (Cornell University) began with the hope that both organizations would continue to engage, learn, and innovate as part of a worldwide collaboration. The goal of the INCOSE panel is to foster an inclusive dialog on Systems Science. The purpose of the dialog is to accelerate the exchange and adoption of tools, techniques, and theories between the two sets of practitioners.

Michael Watson (NASA) shared with the attendees that the upcoming release of System Engineering Principles will include Sociology as a topic. By setting out the fifteen principles of Systems Engineering in a concise manner, System Dynamics solutions can be applied to the principles. Common patterns which apply across domains or across principles will provide leverage for other contributors.

Javier Calvo-Amodo (Oregon State University) shared insights from the perspective of building Systems Science disciplines and that students can participate with journal articles. Since System Dynamics provides a specific lens through which to view models, it can be used to validate the findings of other modeling types or to provide insights into what other modeling systems might reveal. A Systems Science map using Randomness and Complexity as the axes provided a guide to where specific System Dynamics developments can be best applied.

Complex systems are engineered by complex organizations.

Watch the recording below

Q&A

Q: Question to Javier: Why are there so few academic programs in Systems Science compared to Systems Engineering? Is this a problem?

A: They require interdisciplinary approaches, which are difficult to implement as they usually would span across different colleges within a university (e.g. College of Science, College of Liberal Arts, College of Business, College of Engineering, etc.)

Q: Question to Javier: What textbooks or papers would you recommend for learning more about systems science theory and the principles of systems science?

A: I recommend the following: Introductory: Cabrera, D., & Colosi, L. (2008). Distinctions, systems, relationships, and perspectives (DSRP): A theory of thinking and of things. Evaluation and Program Planning, 31(3), 311-316. and Cabrera, D., & Cabrera, L. (2022). DSRP Theory: A Primer. Systems, 10(2), 26.

Original work on systems science: Bertalanffy, A. R., Boulding, K. E., Ashby, W. R., Mead, M., & Bateson, G. (1968). L. von Bertalanffy, General System Theory. New York: George Braziller. and Von Bertalanffy, L. (2010). General systems theory. The Science of Synthesis: Exploring the Social Implications of General Systems Theory, 103.

Latest work on systems science: Rousseau, D. (2015). General systems theory: Its present and potential. Systems Research and Behavioral Science, 32(5), 522-533.;

Rousseau, D. (2018). On the architecture of systemology and the typology of its principles. Systems, 6(1), 7.

Rousseau, D., Billingham, J., Wilby, J., & Blachfellner, S. (2016). In search of general systems theory. Systema, 4(1).;

Rousseau, D. (2018). A framework for understanding systems principles and methods. Insight, 21(3), 9-18.;

Rousseau, D., Billingham, J., & Calvo-Amodio, J. (2018). Systemic semantics: A systems approach to building ontologies and concept maps. Systems, 6(3), 32.

Q: Can you suggest further introductory reading on category theory? This is new to me and a bit uncomfortable with this framing

A: Conceptual Mathematics by William Lawrence

Q: One thing caught my attention comments from Mike…. we need …. “to help build the complex system” and this…. helps… “development of a complex system”…. this is quite different from the underlying philosophy of System Dynamics where the emphasis is often trying to understand an existing system and adjust

A: The difference is in the context and/or domain of application; SD is designed to understand the underlying structures that give rise to System Dynamics as a means to understand from a high-level perspective how the system works. While useful for that purpose, the SD perspective places its main focus on control through feedback and feedforward loops, which may not capture other systemic and holistic arguments necessary to realize a complex engineered system. This is in alignment with Prof. Mike Jackson’s CST and CSP.

Q: Michael’s explanation of Category Theory introduced several concepts that are new (at least, new to me). Does INCOSE offer an introductory reference to supplement his insights?

Yes, go to INCOSE Systems Science Working Group Wiki and search in meetings. We have several presentations by Category Theorists in the meetings section.

Q: How would you differentiate between detailed complexity and dynamic complexity?

A: Those are two kinds of complexities that might or might not be present at the same time.

Q: The term engineering can mean the designing of a system, but is also heavily based on the activity of problem-solving. System Dynamics has problem-solving very strongly in its intellectual foreground. How are the latter activity and strength of System Dynamics used in Systems Sciences activities?

A: Causal loop diagrams and if needed the following simulation can be very powerful to help initial conceptualizations of complex problems. But they rarely yield the full answer; mostly because the models are difficult to verify and validate rigorously (especially if what is being designed is new and there is no frame of reference).

Q: Systems thinking means many things to many people some of these definitions are very loose and perhaps meaningless… is this a problem? Can it be fixed?

A: We believe that Derek Cabrera’s definition is quite good (it was developed using the scientific method). See Cabrera, D., & Colosi, L. (2008). Distinctions, systems, relationships, and perspectives (DSRP): A theory of thinking and of things. Evaluation and Program Planning, 31(3), 311-316. and Cabrera, D., & Cabrera, L. (2022). DSRP Theory: A Primer. Systems, 10(2), 26.

Q: How do we reduce the distance between the research and practice in Systems Engineering? The gap is much wider than, say, between physics and electrical engineering.

A: That is an excellent question that requires a much longer answer than what I can provide here. At the Systems Science Working Group, we are tackling exactly that. What I can say for certain is that we first MUST begin by defining the theoretical foundations for systems engineering. We have several projects working on that. Join us at INCOSE International Workshop to learn more.

Q: Can one mention articles and cases where the presented principles (of both speakers) are applied?

A: Calvo-Amodio, J., & Rousseau, D. (2019). The human activity system: Emergence from purpose, boundaries, relationships, and context. Procedia Computer Science, 153, 91-99. ;

Kittelman, S., Calvo‐Amodio, J., & Martínez León, H. C. (2018). A systems analysis of communication: defining the nature of and principles for communication within human activity systems. Systems Research and Behavioral Science, 35(5), 520-537.;

Taylor, S., Calvo-Amodio, J., & Well, J. (2020). A method for measuring systems thinking learning. Systems, 8(2), 11.;

Q: Why haven’t we seen System Dynamics modeling get as much attention as did machine learning modeling in recent years?

A: It is difficult to verify and validate rigorously.

Q: Does “Organized simplicity” equate to a reductionist approach?

A: Not quite, but the reductionist approach is most efficient in an organized simplicity

Q: Can you please talk about the role of soft systems methods (problem structuring methods for example) in systems engineering? They are useful in scoping poorly understood problem spaces but you rarely see them linked directly to System Engineer.

A: They are very useful to help address the social aspects of Systems Engineer endeavors (John Warfield and Peter Checkland developed their approaches (IM and SSM) to help with this issue); however, it is important to have frameworks that help us integrate all approaches. Mike Jackson’s CST and CSP are great foundations.

Q: Any books you’d recommend?

Mike Jackson’s 2019: Managing Complexity

Q: In System Dynamics, we often talk about the dynamic problem and the reference mode, then try to mode the system with the dynamic problem in mind. What might be the code switch for Systems Engineering’s approach?

A: There is no code switch conceptually. I would say that in Systems Engineer we look at requirements, value, or mission, and we design based on those (maybe similar to dynamic hypotheses, but not quite the same). We use MBSE (model-based System Engineer), in particular, a digital twin as the closest to a reference mode, but these are not isomorphic.

 

Erika Palmer is a Senior Lecturer in the Cornell Systems Engineering Program. She is the founder and chair of the Social Systems Working Group (SocWG) at the International Council for Systems Engineering (INCOSE); the Americas lead for Empowering Women Leaders in Systems Engineering (EWLSE) at INCOSE and represents Cornell on INCOSE’s Academic Council.

Michael D. Watson is the chair of the INCOSE Complex Systems Working Group and chair of the Systems Engineering Principles Action Team. He is the Technical Advisor in the National Aeronautics and Space Administration (NASA) Marshall Space Flight Center (MSFC) Advanced Concepts Office. He graduated with a BSEE from the University of Kentucky in 1987 and obtained his MSE in Electrical and Computer Engineering (1996) and Ph.D. in Electrical and Computer Engineering (2005) from the University of Alabama in Huntsville.

Javier Calvo-Amodio is an Associate Professor of Industrial Engineering at Oregon State University; Chair of the Systems Science Working Group at INCOSE and Deputy Editor of Systems Research and Behavioral Science Journal. His research focus is on developing a fundamental understanding of how to integrate systems science into industrial and systems engineering research and practice to enable better engineering purposeful human activity systems.

Present at the Seminar Series

The Society Seminar Series consists of periodic online meetings on topics of interest to the systems thinking and System Dynamics communities. These virtual activities cover a wide range of topics that cross many domains while bringing together academics, practitioners, and students together for learning and lively discussion. Send your seminar proposal here

Sponsor a Seminar

The Society is actively looking for Seminar sponsors. This allows making a seminar open to all and free of charge. If your organization would like to sponsor one of these events, where you can promote your organization, firm or software, for instance, contact us at office@systemdynamics.org

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us

Can You Fix the American Health Care System? ReThink Health Dynamics

Can You Fix the American Health Care System? ReThink Health Dynamics

Experience first hand the ReThink Health Dynamics Model used by Dartmouth, Brown, MIT, Atlanta, San Diego, Cincinnati, and many other universities and communities throughout the United States. Thousands have come together to explore how they might steward regional resources to achieve the Triple Aim (improve health, cut costs, and quality of care) and beyond (equity and worker productivity).

In this webinar, we:

• Learned how this System Dynamics simulation model has been used to create change,

• Converged on a sound strategy for achieving the Triple Aim, and

• Got a chance to test drive the simulation in an experience much as the one had by real communities doing real work.

And the best part is that this simulation is free for classroom and community use, so you can provoke a more fruitful conversation about how we can make real progress in population health.

Learn more about the Seminar Series.

Watch the recording below

Whoops, this recording is available for members only. If you have a membership, please log in. If not, you can definitely get access! Purchase a membership here. If you're not a member but have purchased a ticket to this webinar, please contact us at office@systemdynamics.

org

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us

ISDC 2021 Highlights: Modeling for Action in Environmental Health

ISDC 2021 Highlights: Modeling for Action in Environmental Health

The International System Dynamics Conference (ISDC) convenes practitioners who demonstrate what’s new and developing in their fields with System Dynamics. This section of the WiSDom Blog, “Conference Highlights,” asks system dynamicists to spotlight key presentations and innovations presented at the conference. 

Conference Highlights Editorial Team: Saras Chung, Will Glass-Husain, Jack Homer, Sara Metcalf, and Remco Peters with coordination by Christine Tang

This highlight by Martha McAlister shares a first-time conference attendee’s perspective on modeling for action in environmental health. 

Modeling for Action in Environmental Health

 

When environmental risks remain unmitigated, they end up hurting our ability to lead healthy and productive lives. These risks are often concentrated where populations are the most marginalized, thereby creating or contributing to unjust health disparities. Environmental health and justice problems can be complex, as they intersect multiple domains (social, economic, political, legal, institutional, etc.) and may involve years or decades of lag time, starting from the accumulation of multiple exposures and ending in life-threatening chronic illnesses. 

System Dynamics offers opportunities for modelers to engage with broad audiences to address environmental health and justice challenges. Modelers can elicit public or expert participation before, during, and after the modeling process to promote confidence in the results and to encourage holistic learning that goes beyond narrowly epidemiological approaches. 

As a first-time attendee of the International System Dynamics Conference, I wanted to learn how System Dynamics is being used in the environmental health context and about the challenges of applying System Dynamics to such complex problems.

The first hint came during the Student-Organized Colloquium, where keynote speaker Dr. Josephine Musango stated that “engagement is crucial.”  As the conference progressed, I heard several presenters talk about their use of participatory modeling to study global environmental and health issues. 

Laurent Smets spoke about using group model building with virology experts to connect early vaccine research and development to the user requirements at the “last mile” in low- and middle-income countries. 

Kelsey Werner described workshops with local community groups in India (organized by the Social Systems Design Lab at Washington University) to model factors affecting their use of less harmful liquefied petroleum gas (e.g., for cooking) in place of solid fuels like firewood or charcoal..

Others reported on using System Dynamics simulation interfaces that engage stakeholders. As Juliette Rooney-Varga put it, this requires translating well-informed scientific models into meaningful, recognizable intervention levers and outputs. 

Allyson Beall King, presenting on her work with Tyler Opp, echoed this concept of scientific translation in describing their model of toxic sediments in Lake Coeur d’Alene.  They wanted to make sure this model would not only satisfy scientists but also be fully accessible and transparent for the public.

I also learned from Daniel Kliem’s talk about how to involve experts in participatory modeling. He said that if a simulation was the ultimate goal, then one should “fail fast” by developing the quantitative model sooner rather than later.  He also advised modelers to remember that we are the translators and integrators of others’ knowledge, and as such we should always give those experts the credit they are due. 

This last point reminded me of something that the other Student-Organized Colloquium keynote speaker, Dr. Irene Headen, said about one of the strengths of System Dynamics: the process allows modelers to collect and integrate multiple perspectives on a single topic. 

The conference is a heady experience for a first-time attendee like myself. Thinking about the presentations I attended, I realize that none precisely addressed environmental health and justice per se.  But that doesn’t really matter, because the presenters made it easy to see how their experiences and insights have broad application, and I look forward to applying these ideas in my own work.     

 

Martha McAlister – mcalisterm@usf.edu

Martha is a PhD student of Environmental Engineering at the University of South Florida. She studies the efficacy and sustainability of environmental health interventions. Martha’s participation in the International System Dynamics Conference was supported by USF NRT Strong Coasts (National Science Foundation under Grant No. 1243510). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation, USF, or NRT Strong Coasts.

 

Check out the Society’s SIGs – including Environmental SIG and Health Policy SIG

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us

System Dynamics for Climate Change Mitigation

System Dynamics for Climate Change Mitigation

We had an insightful Webinar with the participation of With Juliette Rooney-Varga, Carolyn McCarthy, Sibel Eker, and Steve Arquitt .

Integrated System Dynamics models of economy and environment have long been used for research and decision support for sustainability problems, starting with the seminal work of World Dynamics and Limits to Growth. We discussed how System Dynamics models support decision-making, stakeholder, and public engagement for climate change and sustainability problems. We reflected on existing models and tools, such as Climate Interactive’s En-ROADS and Millennium Institute’s iSDG tool, and their use cases. We also discussed how the Climate Change Initiative at UMass Lowell uses System Dynamics tools to raise awareness on climate change.

If you’re a member, you can watch the webinar recording here.

Below are the answers to questions asked live during the Webinar.

Learn more about the Seminar Series.

Q&A Seminar | System Dynamics for Climate Change

Climate Interactive:

How would you describe the interaction between complex models (GCMs …) and simpler system dynamic models in more detail? (how can they support each other?)

Shortly, large detailed models help for cross-validating the simpler models. In return, simple models support the complex models in stakeholder engagement and scenario co-production.

What are the similarities between the EN-Roads Model & the iSDG Model? What are the main differences?

Both EN-Roads and iSDG are based on the System Dynamics method. Both emphasize transparancy, user friendliness, and shared learning. Both place great emphasis on facilitation and support in shared learning. The differences: EN-Roads is a global model, where iSDG is customized to support planning in a particular country or geographic region. EN-Roads is focused on strategies to keep global temperature below a specified level, where iSDG’s focus is more diffuse taking on all the SDGs.

What are some of the major impacts that the Climate Interactive team see on the application side of the models?

This question was not clear to me during the webinar. If “application” means the use of Climate Interactive’s models, we see quite a substantial impact. Only En-ROADS has been used in 73 different countries so far, engaging almost 63000 people. We have a wide audience, from policymakers and philantropists to higher education students and community members. One of the most striking and uplifting recent examples of En-ROADS outreach is the events organized by one of our ambassadors with smallholder farmers in Tanzania. 

Why don’t you use python as the intermediate language? Thanks

Answered during the webinar. Python is a user-friendly language but not as fast as C. We need speed in interactive simulators, so the Vensim model is converted to C.

Are system dynamics models being used in conjunction with Big data and AI?Can system dynamics models learn with machine learning?

There are initiatives about this as far as I know, and ML is very useful for quantifying empirical relationships, but outsourcing the model building completely to AI is not possible, neither desirable in my opinion. System Dynamics’s main strength lies in its descriptive nature, accessibility and understandability. While a hard coupling of SD and machine learning can provide many benefits, it might override the main strengths.

Since there seems to be many questions/comments regarding implementation/compliance, might it be helpful to start focusing on modeling the topic of governance itself, in order to identify and understand the influencing dynamics and loops on the gaps between the ideal solutions actually implemented?

In general, especially regarding specific sustainability governance problems, I agree that this should be the approach, because problem delineation and understanding the system strructure is key to developing any solution. In En-ROADS, though, the primary purpose is public engagement around the topic of “solutions”, hence the underlying dynamics are not co-modelled but shared with the users through various indicators and graphs.

Does the Climate Interactive climate-economy feedback have anything to do with Nordhaus’ “damage” function?

Since En-ROADS is an interactive simulator, it includes a damage function that allows the users to experiment with various “damage functions” found in the literature, including Nordhaus, or make their own assumptions. You can read more about it here 

When will the nature-based/land-based parts in En-ROADS be accessible online?

In the next few months. Please check either the En-ROADS simulator or this page

Very interesting presentation Sibel. Can SDeverywhere and the implementation into a website be done by somebody completely unfamiliar with C or Java or any programming? Many thanks.

I must say that it would be a bit challenging for someone who has no programming experience. There are guidelines, though, which might be helpful to get started.

Questions to Millennium Institute

What are the similarities between the EN-Roads Model & the iSDG Model? What are the main differences?

Both EN-Roads and iSDG are based on the System Dynamics method. Both emphasize transparancy, user friendliness, and shared learning. Both place great emphasis on facilitation and support in shared learning. The differences: EN-Roads is a global model, where iSDG is customized to support planning in a particular country or geographic region. EN-Roads is focused on strategies to keep global temperature below a specified level, where iSDG’s focus is more diffuse taking on all the SDGs.

Are parts of iSDG Model publically available?

Yes, go to www.millennium-institute.org/isdg . There you can access a demonstration model, videos on the iSDG, and the model documentation.

To what extent is the Millennium Institute SDG model open source? It would be so nice to use it rather than starting modelling from scratch in every research project.

At this time the iSDG is not open source. iSDG models are developed within the frame of a specific project. However, much can be learned about the model and its structure by visiting www.millennium-institute.org/isdg.

@Steve, how do you integrate “indicators” of SDG’s to report a single metric?

The iSDG reports the status of each of the 17 SGDs separately. The level of performance of the targets falling under each SDG are averaged to calculate the SDG performance. Targets can be thought of as desired levels of indicators. For a complete explanation see https://www.pnas.org/content/pnas/suppl/2019/10/29/1817276116.DCSupplemental/pnas.1817276116.sapp.pdf

SDG and how it is implemented in real world is highly context-dependence – how iSDG address this?

The iSDG is customized for the country or regional setting. Workshops are held with local experts, decision-makers, and stakeholders who review the model and identify key issues and policies to include inthe iSDG model.

Steve’s question regarding connecting real action to the plan is important. How do we make the interactive modeling tools an integral part of follow up and feedback on action?

With climate change and the SDGs both this really hits the crux of the matter. With the iSDG it is important to involve a broad spectrum of stakeholders on the modeling team and in the workshops who are motivated to see that the selected scenarios are being transformed into policies and then funded. This will require a well-trained team that can run scenarios, derive policies and work with the relevant government people to assure implementation. Monitoring is essential, and needs to be built into the projects. I fully agree with Juliette that the models need to engage with citizens who will then push leaders to make the necessary changes. I would love to hear others’ ideas and experiences on this.

Why choose poverty as a key #1 SDG?

“No poverty” as SDG1 was defined and designated by agreement of the 193 Agenda 2030 signatory countries. There is debate about which SDG is the most important. The iSDG takes no position on which SDG is the most important However, in the iSDG poverty is linked to almost every SDG.

Is this model (MI iSDG Tool) built in STELLA?

If you mean the iSDG, yes the model I showed was built in STELLA however we also have a version in Vensim.

What are some of the active projects that MI is doing today?

Currently we are working on iSDG projects in Afghanistan, Bhutan, China, Uganda, Namibia, Djibouti, Kenya, Democratic Republic of the Congo.

This question–or 2 questions–are for Steve. First, are worldviews and values included in the iSDG models? If so, how? A second question relates to how the highest-level decision-makers regard the models. I’m new to SDS but spent a number of years working with a roughly analogous set of high-level

After some relection, worldviews and values are pervasive in the iSDG model by virtue of the SDGs themselves. iSDG is intended to help policy-makers design strategies and allocate resources for attaining the SDGs. This includes the “leave no one behind” principle, gender equity in education and economic opportunities, equitable income distribution, preserving biodiversity for future generations, rule of law and many others.

Questions to CCI

@CCI any tips on how to engage kids with these tools?

Find resources: Comprehensive Facilitator Resources  Online World Climate Resources

Steve’s question regarding connecting real action to the plan is important. How do we make the interactive modeling tools an integral part of follow up and feedback on action?

Watch the recording for a full answer

@Juliette, could you say a bit about hope? There is a political divide especially in the US, but I read recently that % of the US population who feels anxious about climate change is ~68%. Could role-play games help deal with this anxiety?

Watch the recording for a full answer

“Research shows that showing people research doesn’t work”. What are your thoughts on this @Juliette?

We agree with John Sterman! But if you want to read more about this research, you can here

Why do you think that higher levels of “hope” begin and end higher with the i-H group?

Watch the recording for a full answer

Was the ethnic cultural diversity in your simulation group meetings more diverse than the photos would suggest? If not it’s concerning that you have a rather restricted sample?

Thank you for this question. The breakdown of participants’ racial and ethnic diversity for Building Consensus for Ambitious Climate Action through the World Climate Simulation can be found on page seven. Limitations relevant to our sample can be found on page 24 and reads, “Our sample was not randomly drawn from the general population and is therefore not expected to be representative of the American public. In addition, because the youngest participants in our study were drawn from programs serving low-income, first-generation-to-college students, age likely correlates with other demographic traits in our sample. We therefore do not claim that the observed effects of the simulation or demographics extend to the general American population.”

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us

Watch the recording below

Whoops, this recording is available for members only. If you have a membership, please log in. If not, you can definitely get access! Purchase a membership here. If you're not a member but have purchased a ticket to this webinar, please contact us at office@systemdynamics.org

System Dynamics Biomedical Modeling

System Dynamics Biomedical Modeling

In this Seminar, authors present their work published on the special issue of the System Dynamics Review on Biomedical Modeling. The special issue brings together new research that explores a fascinating array of biomedical problems, from the modeling of pharmacokinetics, hematologic disorders, and blood cell production to chronic disease progression at an aggregate level. System Dynamics health modelers engage with interdisciplinary teams of medical and policy experts in order to explore exciting new biomedical research opportunities.

Learn more about the Seminar Series.

Watch the recording below

Whoops, this recording is available for members only. If you have a membership, please log in. If not, you can definitely get access! Purchase a membership here. If you're not a member but have purchased a ticket to this webinar, please contact us at office@systemdynamics.org

Here some answered questions from the Q&A Session!

Which critical data elements should one collect to gather further insight into model behavior? Were you able to collect medical data to calibrate your model? If not, what are the main drawbacks with respect to your conclusions?

We had to use existing data in the literature for model calibration. But of course, we had some problems with that. First, the data we found was not exact numerical values, rather they were presented in graphs. Second, individual data of patients were not included, giving all the statistics as sample averages. Therefore, we could not delve more into the personalization aspect. Additionally, the literature lacked sufficient blood count data under chemotherapy, making it difficult to calibrate for different chemotherapy regimens. What we actually needed was continuous, or at least a high frequency, time-dependent neutrophil counts for individuals with different characteristics, for example, neutrophil response to a single G-CSF shot for 40 hours and blood cell response in a single chemotherapy cycle. [by Orkun İrsoy & Şanser Güz]

How did you come up with alternative treatments? Was it through experimentation or optimization? 

Since our main focus was not concentrated on finding an ‘optimal’ treatment, we didn’t use any dose & timing optimization procedure. Effectively, our strategy landscape for treatment protocols at https://www.ctontario.ca/review/online-pharmacy/ is defined by two factors: G-CSF Starting Time and G-CSF Injection Count. The standard protocol starts G-CSF supplementation by the end of the fourth day and continues until the next cycle of chemotherapy. Thus, increasing the injections from the end was not an option as it interferes with the next cycle. In our analysis, we reduced the number of injections to create our alternative protocols, to observe the effects of over-and under-stimulation dynamics. We also tested protocols with different starting times (results included in electronic supplement), but the inferences were no different than the one we derived from our current array of protocols. [by Orkun İrsoy & Şanser Güz]

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us

Behavioral Dynamics of COVID-19

Behavioral Dynamics of COVID-19

Over a year since the World Health Organization declared COVID-19 a pandemic, its true global magnitude remains unknown.  Official counts of cases and deaths are known to underestimate the true magnitude of the pandemic, but how much remains uncertain.  Differences in testing and treatment capacity, unknowns like asymptomatic transmission, and most importantly, variable responses to the risk of the virus create wide variation in incidence, prevalence, and mortality across countries and over time. This isn’t just about getting the stats right.  If official counts of cases and deaths are too low, people may not take adequate precautions and governments may (and have) re-opened their economies too soon, leading to more deaths.  Effective responses to the pandemic require an understanding of how these factors interact to shape its trajectory.

To address this need, we developed a model that accounts for behavioral factors such as risk-driven contact reduction, improved treatment, and adherence fatigue, as well as asymptomatic transmission, impacts of weather, disease acuity, and testing and hospital capacity. Estimating this model across all nations that publish sufficient data—a total of 92, spanning about 5 billion people —we found the actual magnitude of the epidemic to be much larger than reported. Specifically, as of the end of 2020, we find cumulative cases were more than seven times larger than official reports, and COVID-19 deaths were about 44% higher than reported. We also found huge variation in death rates, with some countries having over 100 times the per capita deaths of others.

The greatest driver of this wide variation is not demographics, weather, or health care capacity, but rather how responsive are the people and governments of each nation to the threat. Do countries act proactively and aggressively to quash any nascent outbreaks, or do they wait until the situation is severe and hospitals overwhelmed before responding?

Some countries, like Australia, China, New Zealand, and Singapore, have been proactive, responding aggressively to even small spikes in cases, and have largely succeeded in bringing their epidemics under control at death rates below 0.1 per million people per day. Even after caseloads and deaths fell, they remained vigilant, kept masks on and gatherings restricted, and continued testing and tracing until the virus was almost completely stamped out. Despite occasional disruptions from new outbreaks, life in these nations has largely stabilized at a new normal, with few cases and deaths.

Others, including the U.S., many European and South American countries, and India, have been more reactive. Seeking to minimize economic disruption, they delayed action until climbing deaths forced their hands. As each wave subsided, under pressure to reopen their economies, they eased restrictions, only to see cases climbing again. Eventually, faced with rapidly growing outbreaks, they have been forced to lock down again anyway.

Ultimately, countries actually have little choice in how much they must reduce contact levels to control the epidemic. Few communities are willing to tolerate unchecked outbreaks and the horrendous number of deaths that result. By choice or the force of intolerable death rates, all countries have to cut back high-risk interactions – keeping people at home, restricting gatherings, avoiding restaurants and travel, and so on – to control the virus. How much these interactions have to be reduced to keep an outbreak from growing depends largely on the contagiousness of the virus itself, and thus remains similar across nations. What varies across countries is how many cases and deaths it takes to induce strong enough actions to reduce contacts to the required threshold, https://buckfirelaw.com/xanax-alprazolam/ bend the curve, and stop the growing outbreak. In short, until vaccination is widespread all communities pay a similar price to sufficiently bring down their contacts, yet the more responsive ones save many more lives.

To help policymakers and the public better understand these dynamics, we created a free online simulator that allows you to experiment with your own scenarios for vaccination and other policies, and to explore how to change the course of the epidemic over the coming months.

The world is working hard to roll out mass vaccination, but it will still be many months before most people are vaccinated worldwide. Understanding the central role of responsiveness in shaping the dynamics of outbreaks remains critical – it is still not too late for a swift response to both minimize economic disruptions and save lives.

Rahmandad, Lim, and Sterman are coauthors of “Behavioral dynamics of COVID-19: estimating under-reporting, multiple waves, and adherence fatigue across 19 nations,” which is forthcoming in System Dynamic Review. Rahmandad and Lim are coauthors of “Risk-Driven Responses to COVID-19 Eliminate the Tradeoff between Lives and Livelihoods.

 

 

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us

Using System Dynamics to Improve Patient Care

Using System Dynamics to Improve Patient Care

By Şanser Güz, Orkun İrsoy, and Naz Beril Akan

Why do many people practice and advocate systems thinking in biomedical sciences? The human body is a system with strong regulatory mechanisms that maintain the steady state of internal physiological conditions, homeostasis. The regulatory mechanisms of various subsystems of the body emerge from the interaction of feedback signals and provide the body with an internal balancing structure against natural disturbances. But what if the disturbances are far from natural, what if they are chronic or repetitive or interfering with the system itself? Such disruptions in those well-regulated homeostatic systems are the possible leverage points where systemic analysis can add a great deal of value.  These valuable insights can range from deepening inferences about the internal causes to providing alternative methods to alleviate the problem.

Hematological dynamics, in particular, is one of the topics well-covered in the field of System Dynamics, not because of its popularity but due to its inherent delay and feedback-rich nature. Unidirectional thinking falls short in providing successful management of such systems, which attracts the system thinkers. Not surprisingly, including ours, 3 out of 4 articles in the special issue of System Dynamics Review on Biomedical Modeling are related to hematological dynamics.

In our recent study, we take on a hematological disorder called chemotherapy-induced neutropenia (CIN). Along with its targets, the malignant tumors, chemotherapy also damages the valuable stem cell stocks in the bone marrow as a “side effect”. So why are stem cells so valuable to begin with? Stem cells are the earliest precursor cells in the blood cell production chain. When their stock is damaged by a strong disturbance such as chemotherapy, it results in a short supply of blood cells which can only be observed after a certain time. Effectively, we are dealing with a physiological high order supply chain residing in the human body. When the chemotherapy hits the production facility, effects are visible at the consumer level (i.e. blood cells in circulation) after several material delays. 

Aforementioned internal homeostatic regulation is strong, however, for a disturbance that is repetitive.  Having delayed effects such as chemotherapy, endogenous mechanisms may prove to be insufficient to address it. Intensive chemotherapy regimens often result in short supply and oscillations in the leading white blood cells of the immune system, the neutrophils, giving rise to chemotherapy-induced neutropenia (CIN). This is a risky condition for a patient having cancer treatment as it leaves the patient with a vulnerable immune system, against even the simplest of infections. Granulocyte-Colony Stimulating Factor (G-CSF) is the supplementary agent used in the treatment of CIN, stimulating neutrophil production from many stages. However, long delays along the blood cell production chain, susceptibility of stem cells to chemotherapy, and mobilizing effect of G-CSF which depletes the neutrophil reservoir, eventually creates multiple trade-offs inhibiting an easy solution.

In our work, “Dynamic trade-offs in granulocyte colony-stimulating factor (G-CSF) administration during chemotherapy”, we modeled the process in the light of available evidence and previous mechanistic models from other domains of research. With this research, we were able to provide insights on which physiological processes are at play in shaping the patient’s response to treatment and which loops are dominant for the prescription of http://www.papsociety.org/xanax-alprazolam-1-mg/ treatment protocols. Even though the base model was built for a standard patient profile, we see this study as an advancement towards personalized treatments of CIN and plan to build on this subject in future research. We imagine a flight simulator that can be calibrated for individual patients that can be used for generating effective personalized treatment protocols. Following this path has the potential to alleviate neutropenia for people under chemotherapy and improve patient care in a personalized manner.

We started studying the management of CIN nearly two years ago as our bachelor’s graduation project topic.  The work evolved continuously during this time period, with its latest output being this journal article. Our group of three worked on this long enough that System Dynamics and chemotherapy-induced neutropenia became one emerged bilateral entity, and it is only half a joke. As we delved deeper into medical literature and System Dynamics simultaneously, we found astonishing similarities in storytelling on both sides. Our task as modelers was to make a necessary language translation between two mediums and to make an adequate implementation of the method at hand. Because of this very similarity, endogenous feedback structures and systems modeling have been well recognized among the people of medicine. Hence, System Dynamics practitioners like us can use this opportunity to direct their work in this domain of research, where the toolset they use has the potential to systemically analyze, give useful returns, and make a positive change.

 

 

Want to learn more about Biomedical Modeling?

Join us for a Seminar on the special issue of the System Dynamics Review! 

June 09 @ 11 am NY

 CALL TO ACTION

  • Find Modelers…do you envision a similar project? contact the society to be connected to modelers to help you out (have it go to rebecca@systemdynamics.org)
  • Join now for free access to the journal

Recent Posts

Data & Uncertainty in System Dynamics

Data & Uncertainty in System Dynamics Jay Forrester cautioned that “fitting curves to past system data can be misleading”. Certainly, that can be true, if the model is deficient. But we can have our cake and eat it too: a good model that passes traditional System...

Modeling for Improved Organizational Staff Diversity

Modeling for Improved Organizational Staff Diversity We cannot all succeed when (more than) half of us are held back. This slightly modified quote is from Malala Yousafzai, the courageous young woman who stood up for her right to be educated. It summarizes the ethos...

Upcoming Events

Recent Business cases

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide

RSC Uses System Dynamics to Increase HVACR Sales Against the Tide “Using the proven Strategy Dynamic process focused our limited resources on organizing strategic issues, identifying the critical resources, and developing the insight to more rapidly create intuitive...

Achieving a Polio-Free World Through System Dynamics Simulation

Achieving a Polio-Free World Through System Dynamics Simulation EXECUTIVE Summary This System Dynamics model underpinned a 192 country resolution to eradicate polio globally and led the Bill and Melinda Gates Foundation to give Rotary International $100 million to...

MasterCard Halts Market Share Slide With Scenario Planning

MasterCard Halts Market Share Slide With Scenario Planning The Problem MasterCard, a major credit card company, once held a dominant market position US Market Share with only one primary competitor, Visa. They woke up one day and realized that, after six years of...

Join us