Jay Forrester – System Dynamics Pioneer and Father of Modern Simulation Passes

This past Wednesday, Dr. Jay W. Forrester – the pioneer of the system dynamics methodology of modeling and simulation and arguably the father of all of modern modeling and simulation passed away. Dr. Forrester created the collection of methods that is known as system dynamics.

System dynamics essentially uses differential equations to describe the stocks and flows that move and govern the behavior of systems as diverse as population growth systems, innovation adoption in a market, the movement of good through a supply chain and even the movement of fluids through a pipe. SD applications are wide and varied and honestly it would take too long to go through all the different applications of that method.

More than system dynamics applications you ought to know that system dynamics also inspired a whole slew of new and innovative modeling and simulation techniques and that even today it is still a powerful force in describing and explaining some of the most important economic, social, political, and business systems that interest a variety of different stakeholders. I cannot overstate the power and the effectiveness of system dynamics models today.

Jay Forrester started out his career as an electrical engineer in the early 1940s. Eventually, he ended up going to graduate school at the Massachusetts Institute of Technology where he focused his research on digital information storage or what we call today computer memory. In the mid-50s he made the transition to the MIT Sloan school of management where he began to focus his research on supply chains and organizations. If you’ve ever taken a course on supply chain management and you came across a section on the Bull Whip effect – well, that was a direct result of his research (it’s also known as the Forrester Effect).

To most computational social scientists he is known as the father of system dynamics. The method uses differential equations and optimization techniques to model any system behavior as a collection of stocks and relationships between those stocks known as flows. The method itself is extremely useful because it relies on computation to find the right answer rather than pure mathematics which can sometimes produce equations that are extremely difficult to solve in closed form.

But later on, his work outgrew descrbing real world systems and began inspiring other forms of modeling and simulation techniques. System dynamics also formed the basis for an entire industry in economic and financial prediction as well as a myriad of other industries. Today, in most business schools there is usually at least one course that includes the methods of system dynamics, and in most of those schools system dynamics is the only modeling and simulation method taught to both undergraduate and graduate students.

But stemming from system dynamics was also these interesting modeling and simulation methods that forms the basis of artificial societies. I would argue that micro simulations, multi-agent system methods, agent-based modeling, and social simulations in general – perhaps even the fundamental idea behind more progressive techniques such as genetic algorithms at least in part or through a goal-specific view – stem from System Dynamics (capitalized for emphasis).

Forrester showed us that there is value in doing modeling and simulation from the ground up by modeling the behavior of individual components of the system and then combining those components to come up with a model that describes the entire system, including the system’s difficult-to-describe nonlinear behavior. That alone is an achievement worthy of lifetime recognition – which of course Dr. Forrester not only deserved but earned throughout his lifetime and now more than ever in his passing.

Today we lost a thought leader, and an inspiration to entire generations of scientists that try to answer some of the world’s most challenging and important questions. May he rest in peace.

Photo Source: Wikipedia