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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.


  • Dear Jay,
    thank you for sharing your long-term view with the world, and thought a great number of people about the value of not to be victim of system structures. Thanks to you, we all better understand the world.
    From Croatia

  • Lynn Johannson

    Terrible news. The world has lost a resonant voice with great timbre.

  • Jay’s scientific approach radically changed my professional life. I’m deeply thankful to Jay for having inspired me a new (learning-oriented) perspective to conceptualize and implement performance management in different organizations. System Dynamics helped me to gain a competitive advantage to frame dynamic and complex issues in my research and teaching profession. Thank you, Jay.

  • Twenty four years ago, I started my PhD at Mannheim University, supervised by Professor Dr. Peter Milling. Having had no contact with System Dynamics during my diploma program, my first task as PhD student was to attend the introductory System Dynamics class and learn this computer-based approach to study dynamic systems. I played the Beer Game, I learned about stocks and flows, about causal loop diagrams and feedback, about delays and nonlinear relations. I developed small models in Dynamo and Vensim and learned how to simulate and analyze them. In 1994, at the 12th Conference of the Systems Dynamics Society in Stirling, Scotland, I heard Jay W. Forrester talk for the first time. I felt encouraged to read his work and reassured to continue studying dynamic systems – and so I did. Developing, simulating and analyzing System Dynamics models and learning from this process is still one of my favorite activities in research, teaching and transfer to practice. I cannot imagine what I would do today without the stimulus of Jay’s powerful ideas. As 2015 President of the Society, I had the honor to enjoy the conference banquet at Jay’s table. I will never forget this evening, and I am deeply grateful.

  • Reflecting on his childhood in Nebraska, Forrester wrote:

    “life must be very practical. It is not theoretical, it is not conceptual without purpose.
    One works to get results”.

    His work in many fields has produced immensely impressive results. Concentrating on the results emerging from the field of system dynamics, one might be forgiven for claiming on Jay Wright
    Forrester’s behalf:

    I know the power of the bond
    Between cause and effect.

    Aeschylus—Agamemnon, 458 BCE (Trans. Hughes)

  • Max Kleemann

    I belong to one of the first generations of SD students who were only indirectly taught his lessens and I did not have the pleasure to get to know Jay personally. His legacy is to enable us to see additional dimensions in what we see when we try to understand the world. He will continue to inspire me far beyond his lifetime and we were fortunate to have him around for so long.
    At a time when “post-truth” diffuses through societies, his teachings become all the more important: It is not necessary to simplify the world beyond recognition to deal with it. There are methods that enable us to deal with quite a bit of complexity.
    I’d be happy if I see the day when the majority of people become skeptical of “simple answers”.

  • Erik Pruyt

    The work of wisdom of Jay Forrester profoundly changed my life and keep on inspiring me every day. Thank you, Professor Forrester, for having developed the System Dynamics method and for encouraging us to address important problems!

  • Edward Roberts

    On June 3, 2010 I gave the Sloan School Convocation Speech and I focused upon those who had affected my own life. “My first MIT boss when I moved from Electrical Engineering graduate school to the then MIT School of Industrial Management was Professor Jay Forrester. He was already well known as the creator of the magnetic memory core for computers and as head of MIT Project Whirlwind, one of the world’s earliest large-scale computer systems. In setting out to create what became System Dynamics, Jay was a boss who handed out “tough love”, but set remarkably high goals and then gave you all the room required to strive for those goals. Jay emphasized the need to act independently and to not cave in to pressures. Coming from a flourishing Nebraska cattle ranch, he once said to me, “Ed, just remember that if you can’t do things your own way here, you can always go back to the ranch.” As a poor boy from Chelsea, I walked out of his office thinking, “What if you don’t have a ranch?” But his message got across to me. I cherish one other quote from Jay that those who know me will recognize in my behavior: “Always speak in black and white, because people listen in shades of gray!”
    Jay was the most important force in my setting of high standards of achievement in every aspect of life. And in working to create System Dynamics along side of him, I developed the ability to think clearly and causally, as Jay taught. He will be sorely missed by those whom he groomed, because he gave them most of himself.
    Ed Roberts

  • Talk with Professor Forrester was always filled with his warm encouragement to younger people. SD continues to change and improve people’s thinkings. We will go ahead with Professor Forrester’s thought. Thank you, Professor Forrester.

  • Dear Jay

    Many many thanks you have given to my academic search for peace in economics.
    Now please sleep in peace.
    We’ll make our world system-dynamically peaceful by carrying over your vision.

    From Awaji Island, Japan