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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.


  • Professor Forrester was undoubtedly one of the greatest thinkers of the 20th Century; many but too few outside the System Dynamics community recognise fully his intellectual tour de force that contributes daily to the better management of businesses, civic & government administration, defence and the environment. Nevertheless, one trusts that he is quite pleased when looking down on us now to see a multitude of people carrying forward his thinking in the 21st Century, however imperfectly.

  • Silvia Regina dos Santos Coelho

    Thank you Jay W. Forrester for your contribution as the creator of the field of system dynamics much used by several areas of science to solve complex problems and his contribution for helping to create the computer age as we all live in today. So thank you so much to sharing this wonderful knowledge with us.

  • What can I say other, than that – as with so many – discovering Jay’s methodology and systems science in general has had a tremendous impact on my life. So while I am of course very sad to hear about Jay’s passing, thankfulness will prevail.

    To me Jay Forrester is the exact antithesis to that famous Cambridge toast: “Here is to pure mathematics – may it never be of any use to anybody!” What Jay started with “Industrial Dynamics” was to be of the greatest possible use to anyone. Even more so, it was not to be used to just tackle “ordinary” problems, but it was to be aimed at the toughest and biggest messes out there: How to improve the world system? How to build sustainable cities?How to run a national economy and (in general) how to design complex systems in a way that would enable “ordinary people” to run them successfully?

    His call for “thinking big”, his call for avoiding the sirens’ lure to present SD as something “simple and easily digested” and to rather recognize its tremendous challenges (and possibilities, of course) being a very hard and powerful discipline only to be mastered by life-long-learners will remain beacons for me in years to come. Thank you, Prof. Forrester.

  • David F. Andersen

    In 1969 my college roommate placed a copy of Jay Forrester’s book, Urban Dynamics, in my hands. My roommate had just completed a course with John Kemeny focused on Jay’s work. Since that day I have been drawn ever more deeply into Jay Forrester’s work and the field that he founded. I cherish and remember clearly talks that I have had with Jay, many of them exhorting me to do more with my professional work and career. Like many others before me and after me, I have worked hard seeking to meet standards that Jay Forrester always set for himself and others in their work. When I grow up, I want to be more like Jay Forrester.

  • Jack Homer

    We should all be grateful that Jay lived a wonderful long life and that we shared in it. I was his teaching assistant in 1978, and I recall how he quietly skewered the other professors involved in co-teaching the class for their inability to do simple stock-flow calculations. After such a “Gotcha!”, he would look at me with a twinkle in his eye, as if to say, “You knew that, of course!”, and in this way I became part of his club. I once again thank Jay for setting high standards of clarity, thoroughness, and forthrightness that we in his field must all follow as heirs to his legacy.

  • Roberto Pasqualino

    I never had the chance to meet Professor Forrester in person, but spent my PhD always trying to follow the values and clarity of mind necessary to face big challenges that he indicated through his work. Incredible form of inspiration for me, I hope I will be able to contribute effectively to the path he started many years ago. Thank you Professor.

  • Maxon Chitawo

    I just joined SD Society a year ago and I have read a lot about Jay Forrester including listening to his bibliography on YouTube. An inventor, innovator, motivator, mentor, leader, the list can go on and on. That is how Jay has lived his life, contributing immensely to making our planet a better world to live in. I am greatly inspired by every article I read written by Jay Forrester. Jay has been a man of great substance.

  • Rick Hubbard

    Words are wholly inadequate to express the degree of admiration held–and inspiration received–from Professor Jay W. Forrester.

    In uncountable ways, his genius (simultaneously gracious and demanding!) will positively affect humanity for eons.

    Thank you, Jay, for the substance…for ways to garner unexpected insights…for enabling a pantheon of thinkers to apply your unique way(s) of thinking about the way things work.

    In ways direct and subtle, you affected everyone who cherishes data, analysis and reasoning.

    Thank you.

    Rick Hubbard
    Chico, CA

  • Saul Kidde

    I owe my last 10 years of research in problem analysis to system dynamics where I cherish the works of Jay. Unfortunately I never got to meet him. I will miss Jay’s insight in feedback system and especially loop dominance analysis where his works have grounded my research. Rest In Peace Jay

  • Alexander Voigt

    Since Prof. Forrester retired before I learned about System Dynamics, I never got to meet him in person. And yet he had a profound impact on my life: when I first learned about the SD methodology it was as if a veil had been lifted from my eyes, I had finally found a way of structuring information that fit how my mind worked. For this I shall always be thankful.