(A glitch on my dial-in just caused mail to be sent out with this title
but no body. this is the post which was intended...)

 "Douglas P. Wilson" <[EMAIL PROTECTED]> wrote:

>I'd like to write a program to run a simulation of the world economy, 
>first to see if Jay's conclusions follow from his own data, and then 
>to do a sensitivity analysis to see what are the most important 
>variables.
>
>I propose to put this program up on the web in source code form as 
>well as compiled binaries, so that everyone can check to see how 
>plausible the model is, and can play with it a bit.

>I do have some expertise in this area, having worked on a simulation 
>of the Canadian air traffic control system in Ottawa a while back, but
>by putting actual source code up on the web I hope to minimize the 
>dependence of the model on my own personal expertise.
>
>To do this, I will need some data, and I hope Jay will be willing to 
>provide the data underlying his own conclusions.
>
>This is just an idea at the moment, but it sounds like a worthwhile 
>project, consistent with my often stated preference for algorithms 
>over arguments, and I don't think it will too difficult.  What do you 
>think?

This is an approach I have advocated for a long time, so of course
I'm all in favour. However there are some important points to make:
a proper simulation is not a trivial project; I had envisioned it
being the product of a team effort in the order of several man-years.
Most importantly, the simulation will be of no value if it is
algorithm-driven. To reflect the true picture, it must be an FSA
(Finite State Automata) model. Algorithms may be deduced from its
results, but not ordained in its construction. The simulation should
model the actions of individual players, and be iterated over cohorts
over time. A well constructed simulation should be able to model
any form of economy one can imagine, and not be limited by the
constrictive assumptions built into an algorithm-driven simulation.

By the way, algorithm-based simulations already exist, and are used 
regularly by economists, which should be a clear demonstration that
they are no damn good. To see an example, check out the International 
Futures model which I believe can still be found at IFS.org.

                                   -Pete Vincent


Reply via email to