Is SD a Software ?
Could SD be taught/mastered in a 5 days course?
Is SD self contained ?
How would be defined a competent SDist ?
Is successful intelligence part of the should-have abilities of a SDist?
There will be a consensus that SDists have to be accredited?
And the list could probably go on and on...and also the efforts of
getting the answers.
Assessment is one of the most difficults issues in education. Defining
what to measure as for accrediting SDists will be an issue of a similar
level of difficulty, provided there is consensus in advancing in that
direction.
IMHO, what could be done is to define a certain continuum in SD
expertise, allowing to position a SD practitioner in a certain stage of
that continuum.
The con I see is that the setting at the detail level of the
requirements for each stage of the continuum will be controversial...
Lets see how this process evolves...
Be well...
Fabian Szulanski
From: "Fabian H. Szulanski" <fabians@swbell.net>
Some questions Re:accreditation
-
"Fabian H. Szulanski"
- Junior Member
- Posts: 2
- Joined: Fri Mar 29, 2002 3:39 am
-
Jay Forrest - SDSG
- Junior Member
- Posts: 9
- Joined: Fri Mar 29, 2002 3:39 am
Some questions Re:accreditation
Hi Fabian!
Fun topic! No! (in the Spanish meaning of No)
My responses
>Is SD a Software ?=20
No
>Could SD be taught/mastered in a 5 days course?
No
>Is SD self contained ?
No
>How would be defined a competent SDist ?
Inadequately. Academics have tried to make SD a science IMO. But companies
and orgs dont want scienctists, they want success and success comes
through application and it is the application of SD in a manner which
generates success where the field is woefully lacking IMO. This is where
the high rate of evolution is which denies encapsulation at this point.
>Is successful intelligence part of the should-have abilities of a SDist?
Not sure I understand the meaning of this question but I think it is
related to above and the answer is yes.
>There will be a consensus that SDists have to be accredited?
You have already read my take on that!
Regards!
Jay
SDSG,LLC=A0 - The Strategic Decision Simulation Group=20
11606 Highgrove Drive
Houston, Texas 77077
Tel:=A0 281-493-5022
Fax: 281-558-3228
E-mail: jayf@sdsg.com
Fun topic! No! (in the Spanish meaning of No)
My responses
>Is SD a Software ?=20
No
>Could SD be taught/mastered in a 5 days course?
No
>Is SD self contained ?
No
>How would be defined a competent SDist ?
Inadequately. Academics have tried to make SD a science IMO. But companies
and orgs dont want scienctists, they want success and success comes
through application and it is the application of SD in a manner which
generates success where the field is woefully lacking IMO. This is where
the high rate of evolution is which denies encapsulation at this point.
>Is successful intelligence part of the should-have abilities of a SDist?
Not sure I understand the meaning of this question but I think it is
related to above and the answer is yes.
>There will be a consensus that SDists have to be accredited?
You have already read my take on that!
Regards!
Jay
SDSG,LLC=A0 - The Strategic Decision Simulation Group=20
11606 Highgrove Drive
Houston, Texas 77077
Tel:=A0 281-493-5022
Fax: 281-558-3228
E-mail: jayf@sdsg.com
-
Bill Harris
- Member
- Posts: 31
- Joined: Fri Mar 29, 2002 3:39 am
Some questions Re:accreditation
Tom,
I think your ideas of a informal (my word, not yours) code of ethics is a
good one. However,
> - thou shalt perform parameter change experiments one at a time
Doesnt the field of design of experiments teach that factorial designs
may be significantly more efficient than changing one parameter at a time
without adding any significant risk of bad conclusions? As I recall, they
have tests to tell you when you incur risks by factorial or fractional
factorial designs; the potential gains can be significant.
This concern about the specifics of one of your proposals really supports
your later statement:
> The hard part for me is defining codes for intervention. How do we know a
It might be nice to start out with a "SD modelers FAQ". One could start
creating a list of such issues as you mentioned that are at the level of
someone who has already read a significant amount of the literature and is
doing modeling, as opposed to the level of what is SD?. Many FAQs seem
to evolve into something fairly useful after somewhat of an informal peer
review process.
BTW, you speak of professional societies. One of my emotional reactions
against the accreditation proposal was that it sounded like you first had
to join the SD Society and then you had to pass a test that they created.
Im not trying to offend anyone, but that did make it sound like a way to
make the SD Society artificially important.
> Perhaps the SD Society could create a set of questions prospective clients
> might ask, along the lines of Sterman, J. D. (1988). A Skeptics Guide to
That sounds like a good idea. Such efforts by professional groups not only
can help but can also lead to others joining as they see something valuable
being generated.
Just my $0.02 worth.
Bill
--
Bill Harris Hewlett-Packard Co.
R&D Engineering Processes Lake Stevens Division
domain: billh@lsid.hp.com M/S 330
phone: (425) 335-2200 8600 Soper Hill Road
fax: (425) 335-2828 Everett, WA 98205-1298
I think your ideas of a informal (my word, not yours) code of ethics is a
good one. However,
> - thou shalt perform parameter change experiments one at a time
Doesnt the field of design of experiments teach that factorial designs
may be significantly more efficient than changing one parameter at a time
without adding any significant risk of bad conclusions? As I recall, they
have tests to tell you when you incur risks by factorial or fractional
factorial designs; the potential gains can be significant.
This concern about the specifics of one of your proposals really supports
your later statement:
> The hard part for me is defining codes for intervention. How do we know a
It might be nice to start out with a "SD modelers FAQ". One could start
creating a list of such issues as you mentioned that are at the level of
someone who has already read a significant amount of the literature and is
doing modeling, as opposed to the level of what is SD?. Many FAQs seem
to evolve into something fairly useful after somewhat of an informal peer
review process.
BTW, you speak of professional societies. One of my emotional reactions
against the accreditation proposal was that it sounded like you first had
to join the SD Society and then you had to pass a test that they created.
Im not trying to offend anyone, but that did make it sound like a way to
make the SD Society artificially important.
> Perhaps the SD Society could create a set of questions prospective clients
> might ask, along the lines of Sterman, J. D. (1988). A Skeptics Guide to
That sounds like a good idea. Such efforts by professional groups not only
can help but can also lead to others joining as they see something valuable
being generated.
Just my $0.02 worth.
Bill
--
Bill Harris Hewlett-Packard Co.
R&D Engineering Processes Lake Stevens Division
domain: billh@lsid.hp.com M/S 330
phone: (425) 335-2200 8600 Soper Hill Road
fax: (425) 335-2828 Everett, WA 98205-1298
-
Tom Fiddaman
- Senior Member
- Posts: 55
- Joined: Fri Mar 29, 2002 3:39 am
Some questions Re:accreditation
Bill,
Thanks for pointing out an issue I should have anticipated.
>> - thou shalt perform parameter change experiments one at a time
>
>Doesnt the field of design of experiments teach that factorial designs
>may be significantly more efficient than changing one parameter at a time
>without adding any significant risk of bad conclusions? As I recall, they
>have tests to tell you when you incur risks by factorial or fractional
>factorial designs; the potential gains can be significant.
Your point is well taken, and I didnt mean to suggest that we should
exclude this kind of experimentation, or any kind of multivariate
sensitivity analysis, as long as its informed by an understanding of
scientific method. I actually had in mind a particular case in the SD
literature in which an excellent practitioner made 2 changes simultaneously
in a model, and attributed the outcome to the wrong one.
I like the idea of creating an SD FAQ, perhaps as a precursor to something
more. It seems to me that there are two purposes to this: to help new
practitioners get up to speed quickly and effectively, and to help
prospective customers choose quality practitioners. I think its easy to
serve the first goal, as new practitioners are likely to be seeking
information about the field. It sounds tougher to reach and inform
prospective customers - any thoughts on how (or whether) to do this?
- Tom
****************************************************
Thomas Fiddaman, Ph.D.
Ventana Systems http://www.vensim.com
34025 Mann Road Tel (360) 793-0903
Sultan, WA 98294 Fax (360) 793-2911
Tom@Vensim.com http://home.earthlink.net/~tomfid/
****************************************************
Thanks for pointing out an issue I should have anticipated.
>> - thou shalt perform parameter change experiments one at a time
>
>Doesnt the field of design of experiments teach that factorial designs
>may be significantly more efficient than changing one parameter at a time
>without adding any significant risk of bad conclusions? As I recall, they
>have tests to tell you when you incur risks by factorial or fractional
>factorial designs; the potential gains can be significant.
Your point is well taken, and I didnt mean to suggest that we should
exclude this kind of experimentation, or any kind of multivariate
sensitivity analysis, as long as its informed by an understanding of
scientific method. I actually had in mind a particular case in the SD
literature in which an excellent practitioner made 2 changes simultaneously
in a model, and attributed the outcome to the wrong one.
I like the idea of creating an SD FAQ, perhaps as a precursor to something
more. It seems to me that there are two purposes to this: to help new
practitioners get up to speed quickly and effectively, and to help
prospective customers choose quality practitioners. I think its easy to
serve the first goal, as new practitioners are likely to be seeking
information about the field. It sounds tougher to reach and inform
prospective customers - any thoughts on how (or whether) to do this?
- Tom
****************************************************
Thomas Fiddaman, Ph.D.
Ventana Systems http://www.vensim.com
34025 Mann Road Tel (360) 793-0903
Sultan, WA 98294 Fax (360) 793-2911
Tom@Vensim.com http://home.earthlink.net/~tomfid/
****************************************************
-
Bill Harris
- Member
- Posts: 31
- Joined: Fri Mar 29, 2002 3:39 am
Some questions Re:accreditation
Tom,
> scientific method. I actually had in mind a particular case in the SD
> literature in which an excellent practitioner made 2 changes simultaneously
> in a model, and attributed the outcome to the wrong one.
This reminds me of an article I read on proofs in mathematics which pointed
out that they are as much a social as a logical affair. That is, even the
best of people striving to produce good proofs dont _really_ know theyve
gotten it right until a number of their peers have reviewed the work and
agreed (or modified) it.
> I like the idea of creating an SD FAQ, perhaps as a precursor to something
> more. It seems to me that there are two purposes to this: to help new
> practitioners get up to speed quickly and effectively, and to help
> prospective customers choose quality practitioners. I think its easy to
> serve the first goal, as new practitioners are likely to be seeking
> information about the field. It sounds tougher to reach and inform
> prospective customers - any thoughts on how (or whether) to do this?
I guess I was thinking about the former. While Im not a bona fide expert,
Id even consider (seriously) helping with the effort. I see the utility
of a FAQ on the level of "Whats a level?", but Im not as interested in
that; theres so much good literature one can find relatively easily, both
books and articles. Im more interested in the level of information that
may border on the "tricks of the trade" for those who are consulting
practitioners in the field, along the lines of what you mentioned as
guidelines. It could also include (definitely not in priority order)
information on when to use CLDs and when to use stocks and flows (so as
not to start another war, it could mention the various serious approaches
to the topic, acknowledging multiple philosophies);
integration methods, dt and how to determine whether your model exhibits
integration problems;
conformance of models with reality (how to test; how to determine if
youre close enough; how close can one really get; how to add features to
a model to improve its accuracy);
common "idioms" of SD models (much like the molecules, I guess);
standard (pragmatic) approaches to model building and to SD interventions
in organizations (starting with focusing on the problem, not the model);
some simple control theory concepts.
As for the latter purpose, what if we started simply with a list of
recommended questions for prospective clients to ask prospective
practitioners? Id be inclined to keep it simple and start with real-world
related questions. That is, Id be most inclined to include a question
that relates to a behavior or knowledge someone found really correlated to
success in an intervention or modeling activity or to failure (as opposed
to imagined success or failure). Thats not to say there arent "good
practice" items one would really like to include, but such lists can become
long laundry lists of attributes. Sort of like TQC, focusing on what has
really happened (gone wrong or gone right) might give this list a focus and
some credibility.
Comments?
Bill
From: Bill Harris <billh@lsid.hp.com>
PS: Out of curiosity, I note that we dont often talk about control theory
concepts in those specific terms, even though SD did come out of control
theory. Ive seen an MIT dissertation from a person whos name always
escapes me (Graham, I think, or was it Greene) which seemed to do in a
quantitative sense what Senges archetypes did in a qualitative sense: give
one some rules of thumb to use in place of detailed simulations. It was
based on a study of simulation models, and it gave guidance into what kind
of dynamic behavior one would see as a function of the delays in the model,
as well as how one would change a model (and thus system) to try to modify
dynamic behavior in specific ways. It seemed handy, and I copied and
occasionally use the list of rules of thumb it contained, but I never see
reference to it or to related developments. (Unfortunately, I cant find
the few pages I copied from it right now to give a better reference.)
--
Bill Harris Hewlett-Packard Co.
R&D Engineering Processes Lake Stevens Division
domain: billh@lsid.hp.com M/S 330
phone: (425) 335-2200 8600 Soper Hill Road
fax: (425) 335-2828 Everett, WA 98205-1298
> scientific method. I actually had in mind a particular case in the SD
> literature in which an excellent practitioner made 2 changes simultaneously
> in a model, and attributed the outcome to the wrong one.
This reminds me of an article I read on proofs in mathematics which pointed
out that they are as much a social as a logical affair. That is, even the
best of people striving to produce good proofs dont _really_ know theyve
gotten it right until a number of their peers have reviewed the work and
agreed (or modified) it.
> I like the idea of creating an SD FAQ, perhaps as a precursor to something
> more. It seems to me that there are two purposes to this: to help new
> practitioners get up to speed quickly and effectively, and to help
> prospective customers choose quality practitioners. I think its easy to
> serve the first goal, as new practitioners are likely to be seeking
> information about the field. It sounds tougher to reach and inform
> prospective customers - any thoughts on how (or whether) to do this?
I guess I was thinking about the former. While Im not a bona fide expert,
Id even consider (seriously) helping with the effort. I see the utility
of a FAQ on the level of "Whats a level?", but Im not as interested in
that; theres so much good literature one can find relatively easily, both
books and articles. Im more interested in the level of information that
may border on the "tricks of the trade" for those who are consulting
practitioners in the field, along the lines of what you mentioned as
guidelines. It could also include (definitely not in priority order)
information on when to use CLDs and when to use stocks and flows (so as
not to start another war, it could mention the various serious approaches
to the topic, acknowledging multiple philosophies);
integration methods, dt and how to determine whether your model exhibits
integration problems;
conformance of models with reality (how to test; how to determine if
youre close enough; how close can one really get; how to add features to
a model to improve its accuracy);
common "idioms" of SD models (much like the molecules, I guess);
standard (pragmatic) approaches to model building and to SD interventions
in organizations (starting with focusing on the problem, not the model);
some simple control theory concepts.
As for the latter purpose, what if we started simply with a list of
recommended questions for prospective clients to ask prospective
practitioners? Id be inclined to keep it simple and start with real-world
related questions. That is, Id be most inclined to include a question
that relates to a behavior or knowledge someone found really correlated to
success in an intervention or modeling activity or to failure (as opposed
to imagined success or failure). Thats not to say there arent "good
practice" items one would really like to include, but such lists can become
long laundry lists of attributes. Sort of like TQC, focusing on what has
really happened (gone wrong or gone right) might give this list a focus and
some credibility.
Comments?
Bill
From: Bill Harris <billh@lsid.hp.com>
PS: Out of curiosity, I note that we dont often talk about control theory
concepts in those specific terms, even though SD did come out of control
theory. Ive seen an MIT dissertation from a person whos name always
escapes me (Graham, I think, or was it Greene) which seemed to do in a
quantitative sense what Senges archetypes did in a qualitative sense: give
one some rules of thumb to use in place of detailed simulations. It was
based on a study of simulation models, and it gave guidance into what kind
of dynamic behavior one would see as a function of the delays in the model,
as well as how one would change a model (and thus system) to try to modify
dynamic behavior in specific ways. It seemed handy, and I copied and
occasionally use the list of rules of thumb it contained, but I never see
reference to it or to related developments. (Unfortunately, I cant find
the few pages I copied from it right now to give a better reference.)
--
Bill Harris Hewlett-Packard Co.
R&D Engineering Processes Lake Stevens Division
domain: billh@lsid.hp.com M/S 330
phone: (425) 335-2200 8600 Soper Hill Road
fax: (425) 335-2828 Everett, WA 98205-1298
Some questions Re:accreditation
Actually I liked Toms injunction to
- thou shalt perform parameter change experiments one at a time.
Changing parameter values one at a time is directed not toward getting
confidence bounds, but rather toward understanding the model. The
injunction should probably be:
- thou shalt take the time to understand your model (and changing
parameters one at a time is a good way to do it).
From: Jim Hines <jimhines@interserv.com>
- thou shalt perform parameter change experiments one at a time.
Changing parameter values one at a time is directed not toward getting
confidence bounds, but rather toward understanding the model. The
injunction should probably be:
- thou shalt take the time to understand your model (and changing
parameters one at a time is a good way to do it).
From: Jim Hines <jimhines@interserv.com>
-
Bill Harris
- Member
- Posts: 31
- Joined: Fri Mar 29, 2002 3:39 am
Some questions Re:accreditation
> theory. Ive seen an MIT dissertation from a person whos name always
> escapes me (Graham, I think, or was it Greene) which seemed to do in a
> quantitative sense what Senges archetypes did in a qualitative sense: give
> one some rules of thumb to use in place of detailed simulations. It was
> based on a study of simulation models, and it gave guidance into what kind
> of dynamic behavior one would see as a function of the delays in the model,
> as well as how one would change a model (and thus system) to try to modify
> dynamic behavior in specific ways. It seemed handy, and I copied and
The reference is "Principles on the Relationship Between Structure and
Behavior of Dynamic Systems", by Alan Karl Graham, approved August, 1977.
Bill
--
Bill Harris Hewlett-Packard Co.
R&D Engineering Processes Lake Stevens Division
domain: billh@lsid.hp.com M/S 330
phone: (425) 335-2200 8600 Soper Hill Road
fax: (425) 335-2828 Everett, WA 98205-1298
> escapes me (Graham, I think, or was it Greene) which seemed to do in a
> quantitative sense what Senges archetypes did in a qualitative sense: give
> one some rules of thumb to use in place of detailed simulations. It was
> based on a study of simulation models, and it gave guidance into what kind
> of dynamic behavior one would see as a function of the delays in the model,
> as well as how one would change a model (and thus system) to try to modify
> dynamic behavior in specific ways. It seemed handy, and I copied and
The reference is "Principles on the Relationship Between Structure and
Behavior of Dynamic Systems", by Alan Karl Graham, approved August, 1977.
Bill
--
Bill Harris Hewlett-Packard Co.
R&D Engineering Processes Lake Stevens Division
domain: billh@lsid.hp.com M/S 330
phone: (425) 335-2200 8600 Soper Hill Road
fax: (425) 335-2828 Everett, WA 98205-1298
Some questions Re:accreditation
Alans thesis is wonderful. You might be interested in knowing that
Alan is with Pugh Roberts. In addition to being one of the leading
system dynamics folks he is also an expert in TQM (and has a relatively
recent book out in that field).
If you liked Alans thesis, you might also be interested in Nathan
Forresters dissertation and Bob Eberleins dissertation -- both done
at the Sloan School, MIT.
Regards,
Jim Hines
LeapTec and MIT
From: Jim Hines <jimhines@interserv.com>
Alan is with Pugh Roberts. In addition to being one of the leading
system dynamics folks he is also an expert in TQM (and has a relatively
recent book out in that field).
If you liked Alans thesis, you might also be interested in Nathan
Forresters dissertation and Bob Eberleins dissertation -- both done
at the Sloan School, MIT.
Regards,
Jim Hines
LeapTec and MIT
From: Jim Hines <jimhines@interserv.com>
-
Bruce Campbell
- Junior Member
- Posts: 9
- Joined: Fri Mar 29, 2002 3:39 am
Some questions Re:accreditation
> The reference is "Principles on the Relationship Between Structure and
> Behavior of Dynamic Systems", by Alan Karl Graham, approved August, 1977.
As a relative beginner in SD this sounds really interesting. Can anyone
tell me (and interested others) how to get hold of a copy. That is, is
it available in any form other than the dissertation?
Thanks,
Bruce Campbell
Joint Research Centre for Advanced Systems Engineering
Macquarie University
Australia 2109
Ph: +61 2 9850 9107
From: Bruce Campbell <bcampbel@mpce.mq.edu.au>
> Behavior of Dynamic Systems", by Alan Karl Graham, approved August, 1977.
As a relative beginner in SD this sounds really interesting. Can anyone
tell me (and interested others) how to get hold of a copy. That is, is
it available in any form other than the dissertation?
Thanks,
Bruce Campbell
Joint Research Centre for Advanced Systems Engineering
Macquarie University
Australia 2109
Ph: +61 2 9850 9107
From: Bruce Campbell <bcampbel@mpce.mq.edu.au>
-
"Jay W. Forrester"
- Senior Member
- Posts: 63
- Joined: Fri Mar 29, 2002 3:39 am
Some questions Re:accreditation
>> The reference is "Principles on the Relationship Between Structure and
>> Behavior of Dynamic Systems", by Alan Karl Graham, approved August, 1977.
>
>As a relative beginner in SD this sounds really interesting. Can anyone
>tell me (and interested others) how to get hold of a copy. That is, is
>it available in any form other than the dissertation?
>
You can inquire about reproduction formats and prices for the dissertation
from the MIT Library Document Services:
docs@mit.edu
---------------------------------------------------------
Jay W. Forrester
jforestr@MIT.EDU
Professor of Management, Emeritus
and Senior Lecturer, Sloan School
Massachusetts Institute of Technology
Room E60-389
Cambridge, MA 02139
tel: 617-253-1571
fax: 617-258-9405
>> Behavior of Dynamic Systems", by Alan Karl Graham, approved August, 1977.
>
>As a relative beginner in SD this sounds really interesting. Can anyone
>tell me (and interested others) how to get hold of a copy. That is, is
>it available in any form other than the dissertation?
>
You can inquire about reproduction formats and prices for the dissertation
from the MIT Library Document Services:
docs@mit.edu
---------------------------------------------------------
Jay W. Forrester
jforestr@MIT.EDU
Professor of Management, Emeritus
and Senior Lecturer, Sloan School
Massachusetts Institute of Technology
Room E60-389
Cambridge, MA 02139
tel: 617-253-1571
fax: 617-258-9405