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Jay Wright Forrester – founder of our field, leader, mentor, guide, and friend – 1918-2016. Born on Bastille Day, “but to my knowledge,” he once said recently, “the French haven’t taken any notice of it yet.” The System Dynamics community has had him in its midst since the late 1950s. We’ve heard his exhortations (and occasional scoldings) over these almost-60 years, and have grown as individuals and as a field from the examples he set for us. In the early years he struck fear in our hearts as we tried to meet his demands. In the later years we realized the warmth that lay under his drive for our perfection, and we are grateful for all of it.

Jay’s quotes are endlessly instructive. He was always challenging: “The solutions to small problems yield small results. … The most important problems are but little more difficult to handle than the unimportant.” He startled us: “The most important decision of the CEO is how to limit growth.” He saw a similar phenomenon in global dynamics: “Relying on technology to solve the problems created by growth is to evade the question of how to slow growth.” He insisted on an endogenous view: “We cause our own problems.” He always sought wise generalizations from his own model-based work: “Even if we manage to find a high leverage point in a complex system, we’re very likely to push the lever in the wrong direction.” He sought to improve practice in management science: “It’s false to assume that accuracy must be achieved before precision is useful.” In his enthusiasm he occasionally overreached: “Only System Dynamics modelers can talk for an hour without contradicting themselves.” (Just recently he moderated that: “Well, maybe twenty minutes.”) He had unwavering, quiet confidence, and urged us to have it too: “Have courage…”

Many of us have memories we cherish and want to share about Jay. This page is for us all. Write what you want others to see and hear. We will all gain from our memories of Jay.


  • One day during my engineering studies, I discovered an old book called World Dynamics in a bookshelf at the office I was using. Studying environmental engineering at the time, I brought the book to read more during Christmas holidays. I spent my entire Christmas holidays replicating the world model equations in a programming language. I was intrigued by how such as complex social problem was converted from ambiguous text to a numerical model with clear logics that could be inspected by anyone. The release of Sterman’s book Business Dynamics made it possible to learn system dynamics independently, without having a SD groups at the University. I then got the opportunity to develop and teach SD courses at my University, and decided to use SD in my PhD as well. The most memorable moments happen when students are exposed to the World3 model or similar groundbreaking SD models: To watch as the cognitive dissonance of an entire class unfolds, in which students have to totally reconsider their previous beliefs.
    In industry work life, I have used system dynamics whenever the opportunity arose, however there is still a long way to go to realise the full potential of system dynamics in management and management consulting.

    Newton’s Principiae Mathematica and his theory of fluents and fluxions gave us the tools to describe how nature works. Forrester’s Industrial Dynamics and theory of stocks and flows gave us the tools to describe how social systems work.

  • Maurice Glucksman

    Everybody has their own story about how they discovered System Dynamics. I’m always fascinated by these because sometimes it a natural progression or in my case its against all odds. I was an Ocean Engineering and Ship Management student learning to design and operate ships. In a Control Theory lecture the professor was sketching a block diagram and writing the differential equations for an unstable control system with really strange performance that flipped from one extreme to another. He sketched the performance on the chalkboard and one of the students said, ‘hey that just like the explosion and collapse of the deer population on the Kaibab Plateau’ and he went on to describe how the shepherds killed the mountain lions and the deer bred like crazy until they ate all the grass and nearly died off. It was such vivid illustration of the dry math on the chalk board that I sought out the student, Tom Forrest, and talked to him after class to find out more.

    That led to astonishing good fortune: the next semester John Sterman invited me to take his class and then over the subsequent years I was mentored by many of Professor Forrester’s students and their mentees: Nat Mass, Barry RIchmond and Rick Park who all passed on too young; James Lyneis, Jim Hines, John Morecroft, Bob Eberlein, Henry Weil, Ken Cooper, Mark Paich, Mark Keough, Kim Warren, Zafer Achi, Andrew Doman, Partha Bose, and Kostas Triantis. That led to decades of discoveries and insights from System Dynamics and I did what I could to pass it to others.

    Years after my first encounter with the Kaibab Plateau story I met Professor Forrester briefly. We were at a conference in the South of France where he was the keynote speaker. His speech was combative and he was aloof but inspiring. After his talk I wanted to relate a few of the fascinating things I’d discovered with System Dynamics including my Kaibab Plateau encounter but it was a scrum around him so all I could say was ‘that was a really interesting talk, thank you so much’ and he moved on to the next well wisher.

    I think Professor Forrester would have been pleased I didn’t need to meet him at all to be hooked on System Dynamics so I regret missing the chance to tell him. Without a doubt he knew how much more powerful it is to be able to pass on System Dynamics as a secondary infection rather than having to do it directly. I didn’t say it then, but this is my chance to make up for it. I hope this is better:

    ‘Thanks Professor Forrester: your inventions changed my life in so many interesting ways and as a consequence I’ve had tools, means and the opportunity to change others’ lives for the better’

    I believe that’s a message Professor Forrester would have had time to listen to and would have been gratified to hear.

  • Peter Senge

    I had the extraordinary opportunity to work with Jay for about 10 years, starting with when he hired me “to do what you see fit” after my masters degree at MIT and then continuing for about 8 years as part of the national economic model team. It hit me the other day taking with Drew Jones that I am the only person still alive from that team. Nat Mass, our director, passed away some ten years ago and our two other members, Gil Low and Dale Runge both died during the project.

  • Chahriar Assad Bakhtiari

    I just saw today in WSJ that Jay passed away last month. I am looking at his smile right now, and will always remember him with very fond memories.

    No need to make any more comments regarding his accomplishments to the betterment of our world. But I would say this, every time I feel that I am maybe past my prime, and that I should perhaps start to even think about slowing down, one of the people that immediately comes to mind is Prof. Forester, and thus I stand corrected.

  • Jay Forrester was an outstanding scientist and social activist. His fundamental books “Industrial dynamics”, “Urban dynamics” and “World dynamics” were translated into Russian and are being applied in Russian universities. We also study his works at our academic classes and quote them in tutorials.
    Jay Forrester is an example for future scientists and researchers. He said that there was no place for scientific research without purpose, scientific research should be practice-oriented and aimed at solving the major problems of the humanity. He said that we needed people who could present system dynamics to society and government. He did a lot for that, giving us an example. I always tell about Jay Forrester to my students – future researchers.
    Forrester left us a will: “I leave you with the challenge to plan for marching upward from the present aimless plateau and start climbing the mountains ahead. We should be able to move sufficient understanding of the behavior of complex systems into the public sector. When that has been accomplished, we will be ready for creating the universities that can train a true profession of system dynamicists.”
    Russian Scientific Community grieves the loss.
    Representative of Russian SDS Community
    Natalya Lychkina

  • Vladimir Shiriaev

    The life’s journey of a wonderful person has ended.

    My familiarity with the field of system dynamics and Jay Forrester started when I was young. I brought his book «World Dynamics» in the USSR one year after it was published in 1971. The book made a great impression on me. Automatic control systems were then the field of my professional activity, and the fact that my professional interests were the sort of interests Jay Forrester had before he even was occupied with the field of System Dynamics in 1956 profoundly influenced on me.

    I provided insight into his seminal works – «Industrial Dynamics», «Urban Dynamics» and «World Dynamics», and since I worked at an institute, I used them for my lecture courses. The ideas, were made the basis of Forrester’s books, were an excellent subject choice for term papers and graduation thesis topics of students.

    I participated in the System Dynamics Society Conference, I had been privileged to know Jay Forrester and his wife. I am thankful to fortune for the opportunity to communicate with a man like Jay Forrester and the opportunity to work toward the field of System Dynamics.

    I wish that the ideas of Prof. Forrester have continued to develop in the works of his disciples and followers.

    Professor Vladimir Shiriaev, Russian Federation

  • Pam Shelley

    Jay’s understandings, beliefs, and interpretations resulted in SD but much more. I had the the privilege of meeting Jay several times, but more importantly, working closely with a number of his colleagues – people whose minds and attitudes were altered by association with Jay. Brilliant people. And importantly, people who truly care about others and the world. So, humbly Jay, thank you for giving me the opportunity to meet those who follow your work.

  • eric wolstenholme

    Jay made an immense contribution to the world and changed my life dramatically.

    I first read his book ‘Industrial Dynamics’ whilst working as a Purchasing Manager in British Coal in 1975. I was in a job I had resorted to having been disillusioned by Operational Research and esoteric computer models. I could see immediately that the transparency of continuous feedback simulation had much more to offer. I gave up a very secure job and took great risk with my life, and my family’s lives, to follow his path. I have never regretted this.

    I had close contact with Jay during the establishment of the System Dynamics Society and the establishment of the System Dynamics Review and when I ran the International System Dynamics conference at Stirling University in Scotland. I remember well that the latter was on his 76th birthday.

    I found him to be a modest and slightly shy man with a dry sense of humour and an intense passion for what he did. He will be sadly missed at a time when the world needs his thinking most.

    Professor Eric Wolstenholme, UK

  • In 1972 I took a course offered at the MIT Sloan School called Principles of Systems. It was there that I first heard Professor Jay Forrester talk about the counterintuitive behavior of social systems. What I learned in that course changed my career and life path forever. Forty-two years later I continue my work in the field of systems thinking. Jay became my thesis advisor at MIT and encouraged me to author the first textbook on system dynamics after Jay’s own Principles text. He also provided me opportunity to teach system dynamics and recognized that my contribution to the field should be in teaching. He saw this before I fully did and that only years later.

    Jay Forrester directly touched the lives of so many of us in this community… we have so much to be grateful for as we mourn his loss.

  • Martin Kunc

    Jay was a pioneer in every sense. We are now discussing behavioral issues when Jay had already presented evidence of their importance more than 50 years ago and kept reminding use about them in the 50th Anniversary of SD in the Boston Conference. We are worried about climate change when his model predicted this outcome more than 40 years ago. Now it is called bullwhip, but Jay disentangled supply chain dynamics many years before the first paper appeared on the issue of bullwhip in Management Science. Huge investments in urban regeneration were made, especially in the core of cities, when Jay advised to do them decades before. Now we are discussing about model documentation and policy formulation, when his books are examples of proper model conceptualization clearly documented and surprising policy formulation.

    We will sorely miss you and your challenges.