REPLY Definition of root cause (SD6832)

[SDMAIL Bill Braun]

Posted by  Bill Braun <bbraun at hlthsys.com>

Jack writes, "Thanks. I don't understand what you mean by "pump 
different content through it." What is "it"? What is "pump"? What is 
"different content"? Also, I don't know what you mean by "the structure 
is just fine."

I interpret the model to mean that the dynamic hypothesis is understood 
to be a function of exogenous parameters, not current policies. By "just 
fine" I meant that the policies explicit in the model are taken to be OK 
as is, no changes are required or needed. By different content, I meant 
that all that is required to achieve desired results is to change the 
values of the exogenous parameters (which you identified as as the high 
leverage points), which in the context of the model, means that people 
only need to autonomously behave better than they are at present (their 
behavior is an independent variable).

Alternately stated, I take Jack to be saying that (based on my 
understanding of the model, and I may be wrong) the structure of the 
problem focus is OK as is, and the root cause is defined as exogenous 
parameters (having been identified as the high leverage points).

I am clarifying, not arguing, my point. I am still curious about my 
interpretation of exogenous parameters as high leverage points. I can 
think of any number of situations where it would be easy/convenient to 
say, "behave better" and the problem would be solved.

Jack inquires into my post on root cause and exogenous variables. After 
some thought, I think my question is generic.

To what degree ought we think of an exogenous parameter as a root cause 
and/or as a high leverage variable, and correspondingly construct models 
based on that?

If such thinking is sound, why build models in the first place? I think 
I would be left with advising a client, "Bill Braun, who is not under 
your control or influence, is behaving badly. If you can get him to stop 
(paradox intended), your problems are solved."

Bill Braun
Posted by  Bill Braun <bbraun at hlthsys.com>
posting date  Sun, 23 Mar 2008 21:11:12 -0400