How the Urban Decay Crisis Was Solved

This is the most thrilling tale about a real world application of system dynamics modeling we've ever encountered. It proves the point that the right model can solve even the most seemingly impossible-to-solve problem.

Below is an extract from chapter one in the Analytical Activism book. Professor Jay Forrester of MIT used the new tool of system dynamics, better known as feedback loop simulation modeling, to solve what had hitherto been considered an unsolvable crisis.

Bolding has been added for ease of skimming.


In the 1950s and 1960s, urban decay and the symptoms it caused was America’s biggest problem. It would eventually reach the crisis stage with the Los Angeles race riot of 1965, which left 34 people dead. Other riots occurred in Newark and Detroit. The problem continued to deteriorate, and in 1968 Martin Luther King Jr. was assassinated, sparking further riots, including some in the nation’s capitol. The riots, high levels of crime, growing discrimination and race hatred, and a host of factors increased white flight from inner cities. Businesses also moved out. This made the urban decay problem even worse, causing a vicious cycle. Despite a plethora of attempted solutions, the problem failed to get better. By the late 1960s the problem looked hopeless.

Into this void stepped Jay Forrester of MIT in 1968. Twenty one years later, in a fascinating address to the international meeting of the System Dynamics Society in 1989, he described how he began helping to solve the urban decay problem, along with the reactions he encountered: (Italics added)

“John F. Collins, who had been mayor of Boston for eight years, decided not to run for re-election. MIT gave him a one year appointment as a Visiting Professor of Urban Affairs, bringing him into the academic orbit to meet students, interact with faculty, and advise the administration on political issues. Collins had been a victim of polio in the epidemic of the mid 1950s and walked with two arm canes, so he needed an office in a building with automobile access to the elevator level. The building with my office was one of the few that qualified. The professor next door to me was away for a year on sabbatical leave, so John Collins ended up in the adjacent office.

“In discussions with Collins about his eight years coping with Boston urban problems I developed the same feeling that I had come to recognize in talking to corporate executives. The story sounded persuasive but it left an uneasy sense that something was wrong or incomplete. So, I suggested to Collins that we might combine our efforts, taking his experience in cities and my background in modeling, and look for interesting insights about cities. He immediately asked how to go about it. I told him we would need advisers who knew a great deal about cities from personal experience, not those whose knowledge came only from study and reading. We needed people who had struggled with cities, worked in them, and knew what really happens. And furthermore, we would not know what would come of the effort, or how long it might take.

The process would be to gather a group that would meet half a day a week, probably for months, to seek insights into the structure and processes of cities that could explain stagnation and unemployment. Collins listened and said, ‘They'll be here on Wednesday afternoon.’ Collins' position in Boston at that time was such that he could call up almost anybody in politics or business, ask for their Wednesday afternoons for a year, and get them. He delivered the people and it was out of the following discussions that Urban Dynamics developed.

“Urban Dynamics was the first of my modeling work that produced strong, emotional reactions. As you know, it suggested that all of the major urban policies that the United States was following lay somewhere between neutral and highly detrimental, from the viewpoint either of the city as an institution, or from the viewpoint of the low-income, unemployed residents. The most damaging policy was to build low-cost housing. At that time, building low-cost housing was believed to be essential to reviving the inner cities.

“The conclusions of our work were not easily accepted. I recall one full professor of social science in our fine institution at MIT coming to me and saying, ‘I don't care whether you're right or wrong, the results are unacceptable.’ So much for academic objectivity! Others, probably believing the same thing, put it more cautiously as, ‘It doesn't make any difference whether you're right or wrong, urban officials and the residents of the inner city will never accept those ideas.’ It turned out that those were the two groups we could count on for support if they became sufficiently involved to understand. That is a very big ‘if’—if they came close enough to understand.

Three to five hours were required to come to an understanding of what urban dynamics was about. Urban officials and members of the black community in the inner city would become more and more negative and more and more emotional during those three to five hours. If they were not a captive audience, they would walk out before they understood and accepted the way in which low-cost housing was a double-edged sword for making urban conditions worse. Such housing used up space where jobs could be created, while drawing in people who needed jobs. Constructing low-cost housing was a powerful process for creating poverty, not alleviating it.

“My first experience with reactions to Urban Dynamics came soon after the book was published [in 1969]. We had been running a four-week urban executive's program twice a year for department-head level people from larger cities to teach various aspects of management. A group was convening shortly after Urban Dynamics came out. I was asked to take a Monday afternoon and a Wednesday morning to present the Urban Dynamics story. I have never had a lecture on any subject, any place, any time go as badly as that Monday afternoon. In the group was a man from the black community in New York who was a member of the city government. He was from Harlem, intelligent, articulate, not buying a thing I was saying, and carrying the group with him. At one point he said, ‘This is just another way to trample on the rights of the poor people and it's immoral.’ At another point he said, ‘You're not dealing with the black versus white problem, and if you're not dealing with the black versus white problem, you're not dealing with the urban problem." And when I said decay and poverty in Harlem in New York or Roxbury in Boston was made worse by too much low-cost housing, not too little, he looked at me and said, ‘I come from Harlem and there's certainly not too much housing in Harlem.’ That is a sample of the afternoon.

“On Tuesday evening, a dinner was held for the group. Neither Collins nor I could go; but several of our students attended. One student called me at home in the evening to report what was fairly obvious anyway—that the group was very hostile. On that bit of encouragement, I started Wednesday morning.

“An hour into Wednesday morning, the New Yorker's comments began to change character. He was no longer tearing down what was being said. His questions began to elicit information. Two hours into the morning, he said, ‘We can't leave the subject here at the end of this morning. We must have another session.’ I ignored the request to see what would happen next. In about twenty minutes, he repeated it. I agreed to meet them again if he could find a time and place in the program. I was not trying to put him off; however, that usually ends such an exchange. But he went to the administration and scheduled another session.

“Later he made an appointment to come to my office to ask that I talk to a group he would invite in New York—his colleagues on his home turf. He sat in my office as relaxed as could be and said, ‘You know, it's not a race problem in New York at all, it's an economic problem,’ after telling me four days earlier that I was not even addressing the urban problem if I was not dealing with the black versus white issue. He gave me a report out of his brief case documenting the amount of empty housing in every borough of New York and the rate at which it was being abandoned. My point had been that too much housing meant that there was too much for the economy of the area to support. He had all the proof right in his brief case. He simply had not realized what his knowledge meant until it was all put together in a new way.

“Two years later a journalist asked me what people thought in the aftermath of Urban Dynamics. I suggested that he talk to others, and especially with the man in New York whom I had not contacted in the intervening two years. After the interview, the journalist called me to report that he had been told that ‘they don't just have a solution to the urban problem up there at MIT, they have the only solution.’ The lesson about urban behavior had stayed clear and alive for two years even back home in his native environment. The five hours of exposure to Urban Dynamics had made a lasting impression.

“But we have not solved the challenge of how to bring enough people across the barrier separating their usual, simple, static viewpoint from a more comprehensive understanding of dynamic complexity.”

The first point of this long passage is that intuitive, common sense solutions to complex social system problems are usually wrong. When faced with proof that a solution they have supported is wrong, people tend to go into denial and anger. But if someone takes the time to explain why a solution is wrong, as Jay Forrester and John Collins did, people generally come around to a new realization, and can even become strong supporters of an alternative and correct solution.

The second point is that if problem solvers use the right tools, even difficult problems can be solved. Presently most problem solvers working on the sustainability problem are using an intuitive approach. The problem is so incredibly complex it demands an analytical approach, using tools such as the one Forrester used to solve the urban decay crisis.


Endnote - The long passage about Jay Forrester’s experience is from here. This was a “Banquet Talk at the international meeting of the System Dynamics Society, in Stuttgart, Germany, July 13, 1989.”

The Marvelous Tool of System Dynamics

System dyanamics is a modeling approacch. It's the swiss army knife of social problems, business problems, and any thorny, impossible-to-understand problem that exhibits inexplicable trends or cyclic behavior over time. That was the main point of the long story on the left.

Believe it or not, system dyamics modeling is so simple it can be taught to fifth grade children:

"The curriculum enabled fifth and sixth graders to learn analytic and synthesis skills previously taught primarily to graduate classes at M. I. T. The positive results achieved seem transferable to broader groups wishing to become familiar with dynamic feedback systems thinking and its applicability to social problems."