Information Technology Reference
In-Depth Information
Quite frequently one may notice that the solution one has devel-
oped does not correctly match the real-world structure, require-
ments, and policies with which one started. The obvious would
be to tune the solution and iron out any deviations from the
hypotheses on which it was developed. System dynamics, however,
says that the real discrepancy, in such situations, is more likely
between the understanding of the policies and the derivation of
the hypotheses from them. It shows that the business analysts have,
possibly, not understood the system's environment and scope, due
to which the hypotheses prepared for further use become incorrect.
To take an example, a retail store has a return policy stating that goods
can be returned within 30 days of the date of purchase. A system gets
built with a business logic embedded in it that checks for the date and
rejects transactions that are invalid. Such a system fails to work when
rolled out to the stores. It turns out that when the requirements for a
return policy were drawn, the analyst ignored other requirements that
were dynamically linked to it, such as the policy for exchanging items,
or for handling damaged goods, or for handling goods recalled by the
manufacturer. The return policy, therefore, is a policy with many dynamic
elements and, based on what Forrester says, the requirements should
consider the larger dynamic model. The right thing to do is not to treat
the return policy as a “business rule in software” problem but rather to
reevaluate the return policy itself for completeness, making sure that it is
corrected first.
Forrester recommends that you look inside for problems. He makes
an interesting and impressive point about data and information by
saying:
“There seems to be a common attitude that the major difficulty
is shortage of information and data … The problem is not
shortage of data but rather our inability to perceive the conse-
quences of the information we already possess. The system
dynamics approach starts with the concepts and information
on which people are already acting. Generally these are suffi-
cient. The available perceptions are then assembled in a com-
puter model that can show the consequences of the well-known
and properly perceived parts of the system. Generally, the
consequences are unexpected … In many instances the known
policies describe a system which actually causes the troubles.
In other words, the known and intended practices of the
