REPLY Structural changes and validity (SD6662)

[SDMAIL George Richardson]

Posted by  George Richardson <gpr at albany.edu>

The writer of this query suggests that system dynamics can not be effective 
in dealing with social problems because we don't know future social system 
structure.  It's worse than that, I suppose, because we can't even know 
current social system structure for sure.  As he says, we can not "validate" 
structure, and we have no test to determine if structure is "stable" over 
time.

If I understand the posting correctly, the implication appears to be that we 
should stop thinking about future social problems because we don't know how 
current social structure will evolve.  Not only should we not model difficult 
current societal problems, we should stop thinking about them in any form, 
since the social structures we'd assume in our thoughts can't be "validated."

I prefer to think that we have to do the best we can to think about societal 
dynamics as they move from the past into the future, rather than refuse to 
try to apply the best tools we currently have for thinking about complex 
dynamic systems.

It helps our courage to remember that "No model has ever been or ever will 
be thoroughly validated. ... 'Useful,' 'illuminating,' or 'inspiring confidence' 
are more apt descriptors applying to models than 'valid'"  [Greenberger et al., 
Models in the Policy Process (1976)].

George P. Richardson
Chair of public administration and policy
Rockefeller College of Public Affairs and Policy
University at Albany - SUNY, Albany, NY 12222
Posted by  George Richardson <gpr at albany.edu>
posting date  Thu, 4 Oct 2007 13:49:11 -0400