Page 204 - The Six Sigma Project Planner

projects should be identified using very specific rules. According to Eliyahu M.
4
Goldratt, the rules are:
1. Identify the system’s constraint(s). Consider a fictitious company that produces
only two products, P and Q. The market demand for P is 100 units per week and
P sells for $90 per unit. The market demand for Q is 50 units per week and Q
sells for $100 per unit. Assume that A, B, C, and D are workers who have
different, noninterchangeable skills and that each worker is available for only
2,400 minutes per week (eight hours per day, five days per week). For
simplicity, assume that there is no variation, waste, etc. in the process. This
process has a constraint, worker B. This fact has profound implications for
selecting Six Sigma projects.

Figure 37. A Simple Process with a Constraint

Q
P
$100U /
$90/U

50U/W k
00
1U/W k
c r Puhae s
D D
t
Pa
r
n
i
U
15 m / i U 5 m
/
n
$5U /
C C B
U
n/
10 m i 5 m 15m U / i
n
i
/
n

U
A B A
U
n

i
/
n

U
n/
15 m i 15m 10m i / U
1
RM RM2 RM3
$20/U $20/U $20/U
2. Decide how to exploit the system’s constraint(s). Look for Six Sigma projects that
minimize waste of the constraint. For example, if the constraint is the market
demand, then we look for Six Sigma projects that provide 100% on-time
delivery. Let’s not waste anything! If the constraint is a machine, focus on
reducing setup time, eliminating scrap, and keeping the machine running as
much as possible.
3. Subordinate everything else to the above decision. Choose Six Sigma projects to
maximize throughput of the constraint. After completing step 2, choose projects
to eliminate waste from downstream processes; once the constraint has been
utilized to create something, we don’t want to lose it due to some downstream
blunder. Then choose projects to ensure that the constraint is always supplied
with adequate nondefective resources from upstream processes. We pursue
upstream processes last because by definition they have slack resources, so

4
Eliyahu M. Goldratt, The Haystack Syndrome: Sifting Information Out of the Data Ocean, North River Press,
Great Barrington, MA, 1990, pp. 59-63.
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