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Jay W. Forrester, of Concord, computer pioneer; at 98

Professor Forrester during a television interview at MIT.MIT Archives/New York times

A trailblazer in computers in the years after World War II, Jay W. Forrester led development of the Whirlwind I, one of the first high-speed digital computers, and devised magnetic core memory, which became the industry standard for years to come.

Then he walked away from that research area at the Massachusetts Institute of Technology to join the faculty of what is now the MIT Sloan School of Management. For him, the field’s most seismic leaps were already in the past.

“By 1956, I felt the pioneering days in digital computers were over,” he said in a 1989 speech. Though such a view “might seem surprising after the major technical advances of the last 30 years,” he added, the advance in how computers “improved in the decade from 1946 to 1956 in speed, reliability, and storage capacity, was greater than in any decade since.”

Professor Forrester, who was 98 when he died in his Concord home Wednesday of complications from prostate cancer, then pivoted from computers into another new field and founded the discipline of system dynamics modeling.


Using the eyes and perceptions of an electrical engineer to study how corporations run, he showed how businesses could better understand the long-term implications of their policies and fix problems that festered within their own cultures. In subsequent decades, system dynamics would provide insight into economic cycles – from great prosperity to troubling recessions – and would influence thinking about population growth, the environment, and climate change.

“What made Jay so special is because of his background in digital computing, he saw, with the advent of the digital computer, the ability to do simulations that were both large-scale and practical,” Nelson Repenning, distinguished professor of system dynamics and organization studies at the Sloan School, said in a prepared statement. “He appreciated that far before anyone.”


John Sterman, the Jay W. Forrester professor of management at the Sloan School, added in a statement that “from the air traffic control system to 3-D printers, from the software companies use to manage their supply chains to the simulations nations use to understand climate change, the world in which we live today was made possible by Jay’s work.”

From his days riding a horse to a one-room schoolhouse as a Nebraska third-grader to his years writing influential economics books such as “Urban Dynamics” (1969) and “World Dynamics” (1971), Professor Forrester covered a lot of ground geographically and intellectually. “I’ve had several careers,” he told MIT Technology Review last year. “Starting with ranch hand.”

Still, he added, when it came to his work at MIT, “I consider the work we have done in systems far more important than anything we’ve done in computers.”

Jay Wright Forrester was born in the now defunct community of Climax, Neb. “If you go and try to find it now, you will find a windmill and a tank,” he said in a 1998 oral history for the Sloan School. His parents — Marmaduke Montrose Forrester, who was known as Duke, and the former Ethel Wright — were homesteaders on a cattle ranch near the tiny town of Anselmo, Neb.

They also taught school to supplement their income. Unlike most other spreads in the area, their ranch had indoor plumbing and running water. It didn’t have electricity, however, until Professor Forrester was in high school, when as a teenager he used salvaged parts to build a wind-driven power system.


In interviews about his childhood, he credited his ranch upbringing and early rural education for his curiosity, inventiveness, and work ethic. Studying among older students in the one-room schoolhouse where his father taught, for example, helped give him the confidence to tackle advanced studies at an early age. And throughout his upbringing, including summers while he attended the University of Nebraska, he did ranch chores and rode horses for miles, inspecting and fixing fences.

Professor Forrester secured a scholarship to cover the university’s tuition of $35 per semester, and switched from studying agriculture to engineering shortly after enrolling. “Herding cattle in Nebraska winter blizzards never had appealed to me,” he said in the 1989 speech.

He moved to Cambridge after graduating with a bachelor’s degree in electrical engineering, partly because MIT offered more financial help than other colleges, he said in 1989. Also, his mother had been a librarian in Springfield “for two or three years in her youth and she knew there was such a thing as MIT. In the Midwest of the United States at that time, MIT had tended to mean the ‘Massachusetts Investor’s Trust,’ not an engineering school.”

Soon after arriving in 1939, he was working on a stability control mechanism for radar during wartime. He was aboard the USS Lexington in the Pacific during a battle when a Japanese torpedo struck the aircraft carrier, but did not sink the vessel.


Returning to Cambridge after his military work, he married Susan Swett in 1946. She had worked in MIT’s payroll office and her brother introduced them. Mrs. Forrester died in 2010.

Professor Forrester received a master’s in electrical engineering from MIT, and he was inducted into the National Inventors Hall of Fame in 1979 for his work on the Whirlwind I and developing magnetic core memory. He also received the National Medal of Technology and Innovation for computer science in 1989.

Upon joining the Sloan School faculty in 1956, he studied General Electric appliance factories in Kentucky that were experiencing significant swings, from seven-day-a-week shifts one year to layoffs the next. The company’s own policies for hiring and inventory created a “kind of instability,” he said in the 1998 oral history, and “that was the beginning of what was then called industrial dynamics,” which applied scientific structural concepts he had learned in engineering to corporate behavior.

In later work with other companies, he would study a business from top to bottom and design a computer simulation model. “I guess you could say he was a conceiver,” said his son Nathan of Boca Grande, Fla. “He would create a theory in his mind about how things work, and then test it with his computer models.”

In addition to his son, leaves a daughter, Judith, of Concord; another son, Ned, of Falmouth; four grandchildren; and two great-grandchildren.


A memorial service will be held at 10 a.m. Dec. 10 in Trinity Episcopal Church in Concord.

From his high school days building a power generator for his family’s ranch through pioneering computer work and developing system dynamics modeling, Professor Forrester always searched for the key point between trying for too much and playing it too safe.

On the cattle ranch, “if things didn’t work, you found out fast,” he said in an interview posted on

“So I think you develop a feeling for where the edge of the cliff is,” he added. “If you step out too far, you’re a crackpot and you fall off. If you stay back too far, you’re just part of the crowd.”

Bryan Marquard can be reached at