Page 179 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

Value Engineering 151

because eventually, all important information on the project is precisely
defined and displayed in the FAST diagram. The FAST diagram is especially
useful in dealing with projects where there might be widely different opinions,
fuzzy understandings, and cloggy definitions among team members, all of
which are very common in the analysis of organizations, operations, and the
service industry. Construction of a FAST diagram tends to pull together the
thinking process of a group to create a dynamic, enthusiastic team.

Determining the basic function is the first step in the construction of a FAST
diagram. The basic function is the function that cannot be eliminated unless
the product is eliminated. There may be more than one, but an effort should
be made to determine the one most likely basic function. We will use
Example 7.5 as a starting point to discuss the FAST diagram.

Example 7.5: Portion of FAST Diagram for Youth Assistance Program
This example is a continuation of Example 7.4. Of all the functions defined in
Example 7.4, eliminate deviancy, identify needs, and assist clients are con-
sidered to be basic functions, because if any of these functions are not
performed, the whole youth assistance program will not perform as intended.
We can easily notice that the functions are not working in isolation; they are
related to each other depending on the overall mission of the system. We can
ask the question, Why do we need these three basic functions, that is, eliminate
deviancy, identify needs, and assist clients? If we think really hard, we may get
to the conclusion: Ah ha, because this is a youth assistance program, all we
want to do is change the life of these troubled youth so they can become better
kids. Then we may come to another function: modify behavior. That is, the
three basic functions are needed because we want to modify behavior. Figure 7.2
illustrates this relationship.

Why How
Eliminate
deviancy

Modify Identify
behavior needs

Assist
clients

Figure 7.2 Relationships between Basic Functions and Higher-Order Functions