System Dynamics modeling in Healthcare/ Pharmaceuticals

Sanjoy Roy · Post by **Sanjoy Roy** » Tue May 25, 2004 4:14 pm

Hi,

I am new to System Dynamics - but based on a recent experience of
participating in the development of a model - I intend to utilize System
Dynamic modelling for health/pharmaceutical policy issues as part of my
graduate work. Could people with experience in this area share some
pointers please.
Thanks and best regards.

Sanjoy ROY
From: ""Sanjoy Roy"" <sroy@hsc.wvu.edu>
Department of Pharmaceutical Systems and Policy &
Center for Rural Emergency Medicine
West Virginia University
Morgantown, WV 26506-9510
Office: (304) 293-0651
Cell: (304) 685-2487

Geoff McDonnell · Post by **Geoff McDonnell** » Fri May 28, 2004 3:44 am

Sanjoy
I have just put together a spreadsheet of references for a course on Health
Systems Simulation.
Included in this are many SD Specific References.
Hopefully this will be available on a website in a few months.
In the meantime I am Happy to share the references with you or other
interested people (email me below)
A new Health Policy Special Interest Group of the SD Society has been formed
and is co-chaired by Jack Homer and myself.
regards
geoff
Dr Geoff McDonnell
Director Adaptive Care Systems
Research Fellow Centre for Health Informatics UNSW
gmcdonne@bigpond.net.au
Mobile 0419 016 116
Phone +612 9386 0993 Fax +612 9386 0992

geoff coyle · Post by **geoff coyle** » Fri May 28, 2004 10:03 am

Sanjoy, in his enthusiasm, is making the old, old, and very bad, mistake of
putting the methodology before the problem. He needs to think about
precisely which health/pharmaceutical policy issues he wishes to address -
and there must be hundreds of them - and he then needs to define at most a
few well-chosen questions to be answered in the selected domain. Only at
that stage will he be able to decide which of the several analytical
methodologies, of which SD is only one, he requires to use for those
questions. Only then could people in the SD community provide some
intelligent 'pointers'.

Perhaps he should discuss this whole question of research strategy with this
supervisor.

Geoff Coyle
From: ""geoff coyle"" <geoff.coyle@btinternet.com>

GBHirsch@aol.com · Post by **GBHirsch@aol.com** » Fri May 28, 2004 1:01 pm

Dear Sanjoy,

There is an extensive literature describing the application of SD to health
care and, to a lesser degree, pharmaceuticals. The best way to start looking
at this is to get the SD bilbliography from the SD Society and search on
keywords such as health and pharmaceuticals. Among the recent work, Jack Homer and
I and our colleagues from Bellingham, Washington presented a paper at last
summer's ISDC on the dynamics of chronic illness including the effects of more
liberal pharmaceutical coverage on outcomes in patients with diabetes and heart
failure. I can send you a copy if you're interested. There is also a Health
Policy Special Interest Group in the SD Society which formed last year and
will be meeting again at this year's ISDC.

Hope this is helpful.

Gary Hirsch
GBHirsch@comcast.net

B.C.Dangerfield · Post by **B.C.Dangerfield** » Fri May 28, 2004 1:22 pm

Sanjoy:

I suggest you attend the upcoming SD Society conference at
Oxford. Here will be presented 15 papers on SD and health care.

Best

Brian.
From: ""B.C.Dangerfield"" <B.C.Dangerfield@salford.ac.uk>

Prof Brian Dangerfield
Professor of Systems Modelling &
Executive Editor, System Dynamics Review
Centre for OR & Applied Statistics
Faculty of Business & Informatics
Maxwell Building
University of Salford
SALFORD M5 4WT
U.K.
Tel: 44 161 295 5315
Fax: 44 161 295 2130

Timothy Quinn · Post by **Timothy Quinn** » Fri May 28, 2004 3:23 pm

Dear Sanjoy,

System Dynamics, as a field, is vast. Let's say you're interested in
19th-century British literature and you ask your English department's
leading luminary to recommend a few good books. How can she answer?--with
great difficulty, because there are thousands of texts and thousands more
volumes of criticism about those texts, keeping academics busy for decades.

However, I think the best place for you to start is John Sterman's
comprehensive treatment: Sterman, J. (2000) Business Dynamics: Systems
Thinking and Modeling for a Complex World. Boston, MA: Irwin McGraw-Hill.
For a quick healthcare policy example to whet your appetite, check out the
Medigap insurance case on pages 175-177.

Also of interest might be Vennix, J., and J. Gubbels. Chapter 5: Knowledge
Elicitation in Conceptual Model Building: A Case Study in Modeling a
Regional Dutch Health Care System, in ""Modeling for Organizational
Learning"", J. Morecroft and J. Sterman, eds. Portland, OR: Productivity
Press, 1994.

>From there, you can go in many different directions. My opinion is that SD
model building looks deceptively straightforward on the surface, but there
are many subtle issues just beneath the surface to which you must attend in
order to do it well. The best approach is to practice model building while
learning and to iterate as much as possible when working on a real SD
project. Creating a huge, complex model is very easy (and very hard to
analyze). Creating a simple, parsimonious model that captures all the
important and relevant behaviors of your problem's system is very hard.

I hope this helps,
Tim Quinn

System Dynamics Group
Sloan School of Management
Massachusetts Institute of Technology

30 Wadsworth Street
Bldg E53, Suite 360
Cambridge, MA 02142

Telephone: 617-258-5585
Email: tdquinn@mit.edu

geoff coyle · Post by **geoff coyle** » Mon May 31, 2004 12:14 pm

Timothy Quinn is absolutely right in encouraging Sanjoy to build small,
elegant, informative models designed to answer well-chosen questions.

Anyone can build a big computer program and I've even heard people boasting
(!) that 'my model has 40000 variables (literally) so it is bigger than
yours'. One such effort needed 119 pages to print out the stock-flow
diagram. That is not a model as it does not simplify reality so as to
provide a tool for thought about the chosen question.

Some people show a slide of the stock/flow diagram and call it the model. It
isn't, it's a picture of the model and the real model is the equations. As
Jay pointed out, very many years ago, the defence of the model lies in the
defence of its details, that is in the equations, not in the behaviour.

The are many other good SD texts. Richardson and Pugh (1981) is excellent
mainly because it is written in the original DYNAMO notation, which is a
good way to understand SD before using one of the modern, icon-based
simulation packages. There's also Bob Cavana's book (it's on my bookshelf
but I just can't see it), Eric Wolstenholme's 'System Enquiry', Wiley 1990,
and there is my 1996 text. Try Juan Rego's 'System Dynamics: An Ever-present
Vision', Oikos, Buenos Aires, 1999. If Sanjoy wants a different take on
strategic modelling that has nothing to do with SD he could try my recent
'Practical Strategy', Pearson Education, 2004.

Anyone who really wants to understand the essence of the analytical art can
do no better than Professor Pat Rivett's outstanding 'The Craft of Decision
Modelling', Wiley 1994.

All this amounts to saying to welcome newcomers like Sanjoy 'look before you
leap into SD'. As Timothy points out, SD is deceptively simple. As I keep
arguing (having done SD for more than 30 years), it's an excellent and
powerful methodology but it's not suited to all problems and never, ever,
bend the problem to suit the technique. Find the technique that's right for
your problem and don't get obsessed with SD.

Best of luck to him.

Geoff Coyle
From: ""geoff coyle"" <geoff.coyle@btinternet.com>