REPLY Meaning of Stock/Level (SD6889)

[SDMAIL Bill Braun]

Posted by  Bill Braun <bbraun at hlthsys.com>

Alan McLucas asks about soft variables and stocks.

Interesting question. Imagine a group of people who work together and 
there are two cups on each person's desk labeled "Trust" and "Doubt". We 
start with ten chits in "Trust" and zero in "Doubt" (i.e., the 
assumption of complete trust). Based on our interactions any of us can 
take a chit from the Trust cup and drop it in the Doubt cup. Likewise we 
can take a chit from Doubt and drop it in Trust.

As a stock/flow diagram it looks like [Trust] > Losing Trust > [Doubt] > 
Gaining Trust > [Trust].

The material chits are a proxy for information/perceptions. At any point 
in time we could bring the system to rest and assess the relative trust 
levels in the group on a continuum ranging from 1.0 (complete trust) to 
0.0 (complete doubt). We could expand the model to include "Expected 
Trust" or "Expected Doubt" based on the flows.

Does that speak to your question, Alan, and is it a valid SD 
representation (albeit metaphorical) of modeling an intangible?

Bill Braun
Posted by  Bill Braun <bbraun at hlthsys.com>
posting date  Wed, 09 Apr 2008 09:02:16 -0400