LOADING ...

Introduction to System Dynamics: Overview

150K+ views   |   1K+ likes   |   28 dislikes   |  
Jul 28, 2014

Thumbs

Introduction to System Dynamics: Overview
Introduction to System Dynamics: Overview thumb Introduction to System Dynamics: Overview thumb Introduction to System Dynamics: Overview thumb

Transcription

  • PROFESSOR: This is a full semester class
  • divided into two half semester pieces.
  • 15.871 is the six unit H-1 class.
  • That's what probably most of you are thinking about doing.
  • What I would urge you to do is to take both halves,
  • because you and I will co-teach the fall semester.
  • The second half is called 15.872.
  • And although we think this first half is good,
  • the real value in terms of developing
  • a meaningful capability for you to be
  • able to use system dynamics and systems thinking effectively
  • will come if you take the full semester.
  • You don't have to exercise that real option today.
  • You can wait make that decision a little later.
  • But think about it for right now for your semester planning.
  • There are five assignments over the course of this semester.
  • So the good news is there are no exams.
  • The bad news is that there are five assignments
  • and this class has a reputation that I believe
  • is reasonably well deserved for having a heavy workload.
  • The reason for that is clear.
  • I can't teach you anything.
  • I know you're giggling over there.
  • But it's absolutely true.
  • I can't teach you anything.
  • All that I can do-- all that we can do
  • is create an opportunity for you to learn for yourself.
  • You have to do it, try it, practice it,
  • if you're going to develop the capability.
  • That is not going to happen by coming to class.
  • Now, you need to come to class, and participation
  • is part of the grade.
  • But that's not sufficient.
  • It's also necessary for you to try everything out.
  • And that is why we have those assignments.
  • You also are going to need to read the textbooks.
  • So this is the book.
  • And it's pretty fat and heavy.
  • You're not going to be asked to read the whole thing.
  • The bad news on that is I wrote it.
  • So I can tell you that it'll definitely cure your insomnia.
  • I don't care if you buy it.
  • Although I always say, if you buy two,
  • then you can kind of go like this all day,
  • and you can save money by quitting your gym membership.
  • But I don't care if you buy it.
  • I do care that you read it.
  • You can't do well on the assignments
  • unless you read the material in the book carefully,
  • and work through some of those examples.
  • Chapter one is what you need to be reading first.
  • The syllabus tells you what to read for every day.
  • In addition, from time to time, we
  • are asking you to read a couple of short case
  • studies or other material.
  • And we'll provide follow up articles
  • from the professional literature from time to time as well.
  • So the question is why?
  • Why do we need something like system dynamics and systems
  • thinking?
  • And I think the answer is not simply
  • that the world is changing faster and faster.
  • Things are accelerating.
  • Everybody knows that.
  • That's kind of the price of admission to the world today.
  • It's that, despite all the tools and methods that we've got,
  • all the analytic power and our cleverness,
  • things are getting harder and harder.
  • And more and more of the policies that we implement
  • are failing to solve the pressing challenges
  • that we face.
  • And this is not what I'm saying this
  • is what the senior leaders and organizations with whom I work,
  • what they tell me.
  • And the thoughtful ones-- the most thoughtful ones--
  • they say it's not just the things
  • are getting harder and more difficult,
  • despite our cleverness and our analytic power,
  • but because of it.
  • That we're too clever for our own good.
  • And I illustrate this traditionally with this picture
  • of one of the leaders of an organization
  • that I've worked with.
  • And here is the poor guy in this office.
  • Now many of you have seen this before,
  • but I think it's just a great representation of what's
  • going on.
  • Like most senior managers or lower level managers,
  • he is completely squeeze by pressures on all sides.
  • Can't breathe.
  • Claustrophobic.
  • And what you're asked to do as a manager is to be decisive.
  • You've got to make decisions.
  • Boo.
  • Things are now much better for you.
  • Now you can begin to breathe more easily,
  • see out to the side.
  • Relief.
  • Things are great.
  • But as you may suspect, there could
  • be some unanticipated side effects.
  • Now, the reason I like this and the reason
  • I'm showing it to you again, so I
  • think it's a great way to capture the core of what
  • a lot of systems thinking is about.
  • Why does this happen?
  • Why does this happen?
  • And why don't people learn?
  • So it's not just that it happens once,
  • but people do it over and over again.
  • So why?
  • That's a real question for you.
  • So what do think?
  • Why might this happen?
  • And why might this phenomenon persist?
  • Yeah go ahead.
  • AUDIENCE: It's only in the short term,
  • and the short-term implications of that action.
  • PROFESSOR: Great.
  • So short-term time rise and not thinking
  • about what might happen later.
  • So apres-moi le deluge.
  • I don't care.
  • I'll do what's good for me in the short run.
  • I don't care if it destroys the world later.
  • OK great.
  • What else?
  • Yeah go ahead.
  • AUDIENCE: Feedback loops.
  • So you would get some feedback and you won't really
  • consider it the way that it really is.
  • PROFESSOR: So there's definitely a feedback loop here, right?
  • And the problem is that it takes too much time
  • for that to happen.
  • So the time delay in getting the feedback-- maybe
  • missing feedback-- is connected to the short time horizon.
  • In fact, what's going to happen in most organizations
  • to this manager right about now?
  • He solved the problem, right?
  • So what happens to him.
  • AUDIENCE: He gets promoted.
  • PROFESSOR: Of course.
  • He gets promoted.
  • You get to sit in the chair.
  • It's a combination of short time horizon,
  • and not only by that guy, but the people
  • who are evaluating his performance
  • and maybe encouraging him to have a short time horizon.
  • That's not going to be good for anybody in this situation.
  • What else?
  • What else might be going on?
  • We get somebody over on this side?
  • [? Argoff, ?] what do you think?
  • AUDIENCE: I think it's also, like you said it was,
  • when you're thinking only short term,
  • you find that can you make a decision without thinking
  • about what the impact of--
  • PROFESSOR: This is a really important point.
  • And let me put it into our terms.
  • When people say, it wasn't my fault, the reason we failed
  • was some outside effect, some unanticipated side effect,
  • something that came from out there.
  • It wasn't my fault.
  • They're trying to persuade you that they, in fact, are
  • great managers and shouldn't be held responsible
  • for the bad outcome.
  • In fact, almost all the time, it is at least partially
  • the result of their own past decisions.
  • Feedback they didn't understand and didn't recognize.
  • And what they're actually trying to do
  • is persuade you that it wasn't their fault.
  • But what they're really communicating
  • is how narrow and blinkered and inadequate
  • is their understanding of the system in which they're
  • embedded, what we would call their mental model.
  • I think that's where you were going.
  • So that's a really important idea
  • in what we're going to be about.
  • So one of the mental models that I think
  • is the most damaging out there is this open loop mental model.
  • And here's the question.
  • In a project that you've been involved in
  • or that you were reviewing, how many times
  • have you seen this picture?
  • Can I see hands?
  • Who's seen it?
  • Almost everybody.
  • Who's drawn it in one of their project proposals?
  • About 3/4 of the same hands.
  • This is a very interesting, unintended revelation
  • of mental models that people hold
  • about complex dynamical systems.
  • And it basically says, there's a beginning and middle and end
  • to the project.
  • We're going to identify the issue.
  • We're going to gather the data, evaluate our choices,
  • select the optimal solution, and then implement.
  • And of course, the students in the last class when I said,
  • what's wrong with this picture?
  • They all said, oh well.
  • You know.
  • You're a professor.
  • So you've never implemented anything in your life.
  • OK.
  • Now, in fact, a lot of my research
  • is devoted to the question of why
  • implementation so often fails.
  • We're going to talk about that.
  • System dynamics isn't useful unless you can actually
  • make things different.
  • If you can't catalyze change in your organizations
  • in which you're engaged, none of this is meaningful.
  • You might as well become a professor.
  • So we're going to talk a lot about--
  • and I mean that in all the negative senses
  • that you're laughing about.
  • We're going to talk about system dynamics in action,
  • especially in the second half of the class.
  • You're going to see a lot of case studies of how people have
  • been able to use these tools effectively
  • in difficult political organizational settings.
  • So that's an issue.
  • But it's not the real problem.
  • The real problem with this is that it has this open loop
  • one-way sequential perspective that
  • says there's a beginning, middle and end to the project.
  • I don't know about you, but no project I ever been involved in
  • has ever gone that way.
  • There's always iteration, feedback.
  • We have to go back to the beginning, almost always
  • unintended, unplanned iteration, because we go through
  • and we find out as we gather the data,
  • we interview the folks that are engaged.
  • And we evaluate our technologies,
  • supply chain for the new product or whatever it is.
  • We really didn't understand the situation.
  • We really didn't understand what the real problem is.
  • We have to loop back to the beginning.
  • This happens continually all the way through the project.
  • And it's that feedback that's critical here.
  • So this is the metaphor that I want you to fix in your mind.
  • You make decisions.
  • Your decisions change the world.
  • And then that creates new information
  • which changes your next decision in a continual, emergent,
  • iterative set of feedback processes.
  • Now let me make this a little more formal.
  • Again, this is a slight review for those of you
  • who have had me in orientation.
  • But it's worth it, especially if you
  • haven't seen this for awhile.
  • So here's that open loop perspective.
  • People say, I know my goals.
  • I want better market share.
  • I want more profitability.
  • I want a bigger house, or a nicer car, whatever it is.
  • That's going to motivate my decisions.
  • And then my decisions are going to change
  • the state of the world, state of the system, problem solved.
  • That's wrong.
  • I can't know what decisions to make
  • just because I know where I want to be.
  • I have to also know where I am right now.
  • There has to be a feedback.
  • So the example I always give is that, I'm a bicycle commuter,
  • and as I was riding into MIT from Lexington
  • this morning, as every day, I must
  • keep my bike on the right hand side of the path.
  • If I don't, I'm going to have a crash.
  • So just knowing that I need to be on the right hand side
  • is not enough for me to know how to turn the handlebars.
  • I have to have the feedback from where my bicycle actually
  • is in order to know which way to turn the handlebars.
  • It is the same for you, driving your car or flying an aircraft.
  • Now if flying your organization through hostile skies, dog
  • fighting with the competition, keeping investors
  • happy and calm in the back, and serving them
  • nice drinks and hors d'oeuvres-- if flying your company
  • was just as easy as flying an aircraft, which
  • isn't that easy by the was.
  • It doesn't take much bad weather, fatigue, or substances
  • in your bloodstream to degrade your abilities so
  • much that you're going to crash the plane, crash your car,
  • or crash your bicycle.
  • But if it was as easy to run your company as it
  • is to ride a bike, no problem.
  • We wouldn't need this class.
  • But it's not.
  • And it's not easy in part, because that feedback loop,
  • which represents the intended effects of your decisions,
  • but doesn't capture the unintended effects.
  • It's only piece of the system.
  • So you're embedded in a much more intricate complex system
  • in which that's what's going on for you.
  • That represents mental models of what you ought to do.
  • But mental models are limited.
  • And all the impacts of your decisions-- all the effects
  • of your decisions that you didn't think about in advance,
  • and that aren't part of your mental model,
  • they're going to manifest as so-called side effects.
  • Remember there's no such thing as a side effect.
  • There's just the effects that are in your mental model
  • that you were counting on and everything else
  • is going to manifest as a so-called side effect.
  • And they're usually going to feedback
  • in a way that's opposite to your goals.
  • Much more interesting, you're not
  • the only player in the world.
  • So there's all the other actors out there,
  • all the other agents out there.
  • And they have their own goals, which are typically
  • different from your goals.
  • You want more market share, so do they.
  • There is only 100% to divide up.
  • And every time you make decisions,
  • even if they're efficacious that pulled
  • the world closer to your goals, they're
  • necessarily going to be pulling the world farther
  • away from those other folks goals--
  • your customers, your suppliers, your employees, the investors,
  • the competitors, the communities in which you operate,
  • the natural world in which all of that is embedded.
  • That's all going to be there.
  • And those goals are going to motivate them to take action,
  • to try to bring the state of the world
  • back to what they want it to be.
  • Their mental models are limited too.
  • And so they're going to generate unintended so-called side
  • effects.
  • And now this is getting to be a fairly complex thing
  • to manage-- not as easy as riding a bicycle.
  • The whole story here is about expanding the boundaries
  • of your mental models so that more and more of this structure
  • is something that you can begin to think about and try
  • to take into account when you make decisions.
  • You're never going to get it all,
  • because all models are wrong.
  • Model is not the real system.
  • Only the reality is the reality.
  • And everything in your head is a limited, filtered, imperfect
  • representation.
  • But we can do a lot better than the mental models
  • that we have now.
  • So what are we going to do?
  • What we're going to do is develop tools
  • in this class to elicit your mental models,
  • articulate them, and do that in the context of busy people
  • in organizations.
  • We're going to explicitly account for feedback,
  • and stocks and foils, and time delays, and non-linearities,
  • and the other elements of complex dynamical systems.
  • And then we're going to use simulation
  • to figure out what that means.
  • Not because the model is going to give us the answer--
  • all models are wrong-- because the simulation models are going
  • to give us insight that improves our mental models
  • and the mental models of all the people
  • who need to be involved in order for change to happen,
  • so that people are empowered with high leverage,
  • effective policies to go out there and make a difference.
  • You can read in the syllabus how we're going to do that.
  • But I think there are three core ideas
  • I'd like to leave you with before we break for today.
  • The first is that it's the structure of complex systems
  • that generates their behavior.
  • That structure consists of the physics
  • of the system, the information that's available to you,
  • and then the decision rules that you
  • used to turn that information into action.
  • All three of those are relevant here.
  • Mental models matter a lot.
  • It is not enough just to come up with the right answer.
  • And it's not enough just to change
  • the physics of the system, or the information with a new IT
  • system, or the incentives that people face.
  • All those are important, but they
  • aren't generally sufficient.
  • And one of the very powerful mental models that's out there
  • is what we call the fundamental attribution
  • error in psychology.
  • And this is an idea you should have learned at the beer game.
  • And it's the idea that if you ask me why I've screwed up,
  • I've got reasons known as excuses.
  • It was the customer's fault.
  • It was somebody else's fault.
  • The sun was in my eyes.
  • But if I'm asked to explain why use screwed up,
  • It's because you're not capable.
  • You don't have what it takes, you and everybody like you.
  • And that is almost always wrong.
  • And it's low leverage.
  • It doesn't help.
  • So to put that into practice in this class, when
  • we come in here, and you work with us this semester,
  • we're going to make the following basic assumption.
  • We believe that everybody in this room is intelligent,
  • is capable, cares about doing their best, and wants to learn.

Download subtitle

Description

MIT 15.871 Introduction to System Dynamics, Fall 2013
View the complete course: http://ocw.mit.edu/15-871F13
Instructor: John Sterman

Professor John Sterman introduces system dynamics and talks about the course.

License: Creative Commons BY-NC-SA
More information at http://ocw.mit.edu/terms
More courses at http://ocw.mit.edu