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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.


  • Ufuk Turen

    I have started my SD journey with his classical works. It was a real enlightment for my intellectual development. This process basically altered the lenses which l looked through. His insight and contributions to humanity by building SD approach deserves the best compliment.

  • Alice

    My most poignant memory of Jay was through his wife Susan who told us a short story of her courtship with Jay over dinner one night. What she told me changed my view of the man Jay Forrester who was famous and somewhat unreachable even though we all were sitting at the table together – a mysterious genius of a man. She looked me right in the eye and said “To me Jay was and will always be a cowboy, my cowboy.”, she smiled and her eyes twinkled.

  • Antonio Barron

    Dear Professor: thanks a lot for teaching us the logic of systems, their internal interrelationships, and how they explain or anticipate their results. Thank you also for your pioneering contributions to computing, which makes life and daily work easier. Thanks to the collaborators and followers of yours have faciltated your knowledge, and rewarded with their friendship. Until forever

  • Luis Luna-Reyes

    The first time I met Jay was in a visit to Albany when I was a PhD student. I was impressed by his sense of humor and humbleness. His work has already transcended and touch many lives.

  • Aminah Zawedde

    I recently completed my PhD that is grounded in systems thinking and System Dynamics, thanks to Jay Forrester for having founded this methodology. His approach to system dynamics greatly contributed to my understanding of systems modelling concepts and theories. Jay lived a great life that has left an everlasting legacy.

  • Chris Johnson

    Am very thankful for (the minor) interactions and memories I was able to have with Jay.

    One time I introduced myself to him as the Lab Manager at GE Research where we do today’s versions of systems simulation and optimization. He was keen to share what he did so many years ago for our Appliances business, I enjoyed sharing that the same dynamics still play out with the names, places and scale of applications changing. Of course he knew that and dead-panned mentioned with a slight twinkle in his eye that ‘many a person has made a nice career from this’. And I’m standing there thinking, hum… he was either not too impressed with our extensions or me as one of those making a nice career of these things. And appreciated after the moment that he masterfully delivered a challenge to a place where he knew it would motivate.

  • Ganiyu Odunusi

    A respectable man (Professor J. Forrester) has departed, it is our hope that his legacy Lives on.

  • Piero Mella

    I’ve never met Jay Forrester in person, but his writings have been of great inspiration to me in understanding not only the world dynamics, but also the control systems that regulate those dynamics. I express my deepest condolences for the loss of this gigantic pioneer in the study of systems.

  • I will always be grateful to system dynamics, Jay Forrester, and the people he mentored for helping me understand that personal valiance cannot overcome behavior generated by a system’s structure, but instead a constructive path for change explores policies for altering the patterns of communication that inform decision making.

  • Jim Hines

    Fortunately, Jay left a stamp on his many students, so his unique viewpoint survives. I was fortunate during eighteen years at MIT to have Jay as my dissertation adviser and then as senior colleague. Jay was original and didn’t shy away from controversy caused by originality. In fact, quite the opposite. He would sometimes say that you could measure the importance of your own work by the stature of those who argued against it. Once at a gathering of macro-engineers Jay delivered a gently devastating assessment of their proposed projects. On his way back from the microphone he passed behind my chair, and I heard him say quietly, “Well, maybe they won’t invite me back next time”. He’s the only person I’ve ever known who would consider a successful talk to be one one that resulted in a determined lack of future invitations.