REPLY Do marginal models marginalize modeling? (SD6732)

[SDMAIL Ralf Lippold]

Posted by  Ralf Lippold <ralf_lippold at web.de>

Jack's comment just has triggered new thinking about the modeling process.

It seems -especially to SD newcomers as myself- specifically difficult to dive 
into the nice areas of modeling. As some of you already have pointed out 
earlier in several other discussions the modeling derives out of a genuine 
learning process. This learning just doesn't come out of nowhere.

There has to be a real and really disturbing problem that one wants to get 
done with!

I rather stick to John Sterman's "Steps of the modeling process" as I like 
the sparkness and clearity of the steps. At first sight it looks too simple 
to be a guideline to get to a working modeling. What is more important is the 
way one has to take to "the model" in question.

As dealing a lot with improvement initiatives that always can led back to mere 
change initiatives system dynamics opens a whole new set of tools in order to 
explain why things don't work as they should. Unearthing the hidden mental 
models through SD methods (such as causal loop diagrams) is a first step make 
the problem for more people understood (besides yourself!).

> From there on one can go deeper into reasoning 
the root causes (by the way one of the techniques that got Toyota in the lead 
of all the other automobile companies around the world). Personally I am this 
phase for quite some while now discussing a common topic with an engineer on 
the other side of the world (to be exact in New Zealand).

Through the constant challenge of his and mine assumptions for the last couple 
of months we are coming close to a common understanding what are -possible- 
reasons that effect the actors in the viewed system. The learning is -in my 
eyes- the essential benefit of this phase and even an experienced model would 
have to ask the "client" (process owner, actors in the "game") what goes on in 
their heads, what their mental models seem to be in order to arrive at solution 
(a model in this case) that everybody is buying in.

The interesting thing during our discussions is that I am coming from an 
economics background (having studied economics and business administration) 
seeing often the facing problem from a broader perspective whereas he as a 
mechanical engineer focuses on more details in the problem discussion. This 
on the other hand propells interesting new paths to the final solution (or 
"mountain" as Geoff Coyle is describing it in one of his articles on model 
building).

> If you would like to see a detailed analysis explaining this, just ask.

@Jack, I would be highly interested in a detailed analysis explaining your thoughts.

> I hope this is making sense and you can follow it.
>
> Step C increases your system understanding greatly, by forcing you to determine why past
> solutions have failed. This is true for all difficult problems. Step C also gets you started
> in thinking in terms of leverage points. Solutions fail when they push on low leverage
> points (LLPs).

Coming from a pure practical background for the last 10 years, working at a railroad 
service provider and a automobile producer I have wondered for quite some time how to 
connect my thinking about the facing problems and their change over time (just happened 
to know of system dynamics about two years ago) to management and peers. For getting 
deeper into the modeling and the fact how this can be transferred to "non systemdynamicists " 
one really has to urge to solve a "personal" problem that solution has a direct impact for 
yourself. So tackling the problem from two different sides follows in diverse learning paths 
and through the collaboration (during our regular discussions via Skype) we accumulate SD 
wisdom which will -supposedly- end up in a working model. ..and if not yet in the next months 
there will be further spiral learning;-).

For the modeler to be successful with the model and the appropriate advice to the client it 
comes into play what Ed Schein calls "process consultancy" in order to make the changes 
sustainable. The "client" has to learn how to solve this very problem with "new" techniques 
such as systems thinking (before he goes to actual modeling) and not being told by an 
experienced modeler.

> A high leverage point (HLP) is not a place in a system where a small change causes a big
> difference, as is the popular definition. By this definition, the Kyoto Protocol treaty
> would be a HLP, because signing the treaty is such a small change and the effect of
> implementing it would cause a large behavior change. But what about the effort it takes to
> get the treaty signed and implemented? So my definition of a HLP is a place in a system
> where a small amount of change force (the effort required to prepare and make a change)
> causes a large amount of predictable, favorable response. This is the familiar ratio of
> input to output.
>
> LLPs are attractive, even to modelers. Richard, I believe that inability to tell a LLP
> from a HLP, and lack of step C in the modeling process, is one reason for the "dumbing
> down" trend. Of course, I'm also arguing that lack of steps A, B, C, D, and E, followed
> by "Use that knowledge and experimentation to converge on a solution." is the greater reason.

The LLP is what Toyota is doing through their KAIZEN strategy where small steps of improvement 
lead to the "big" change over time. The benefits of LLP are that the don't disturb the system 
as a whole as much (or not at all) as would a HLP such as the mentioned Kyoto Protocol). Through 
sustainable improvements (that's the difficult part of the equation, as this doesn't come 
naturally because the systems view is not very common around workforces that work in separate 
processes (much like a silo!) the small improvements will accumulate and finally -after some 
time- will end in better results (measured in produced widgets, customer satisfaction, 
productivity, decrease of defects, and alike).

Looking forward to seeing other's ideas on the modeling process (especially from other people 
who sidestepped into System Dynamics as myself).

Cheers

Ralf
Posted by  Ralf Lippold <ralf_lippold at web.de>
posting date  Thu, 7 Feb 2008 15:01:40 +0100