Page 181 - Lean six sigma demystified
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160 Lean Six Sigma DemystifieD
n = 105518 Annual unnecessary repair appointments
105,518 100%
96,750 92%
90%
92,328 80%
Number of unnecessary repair appointments 65,949 60%
79,139
70%
50%
52,759
40%
39,569
26,380
20%
13,190 8,768 30%
10%
– 0%
Loop test okay Miscellaneous
Cause of unnecessary appointment
FIGURE 5-8 • Loop test okay Pareto chart.
knee-jerk reaction was to demand that every repair have an appointment. (In
Lean, this is classic overproduction.) To be polite, we attributed the problem to
not using the loop test to determine the need for an appointment (Fig. 5-9).
We diagnosed this problem on a Thursday, and by the following Monday the
RSA managers had implemented the change (Fig. 5-10). Unnecessary appoint-
ments fell from 9,000 per month to 50 a week almost overnight (Fig. 5-11).
(Some problems, like junction boxes and transmission lines, were still outside
of the home.) I can tell you that the repair managers were sweating bullets over
this change. They figured that their repair staff would waste a lot of time going
to houses where no one was home, but fortunately we also measured the num-
ber of times that customer’s weren’t home for the repair. This measurement
didn’t move a hair. In a few days time we had collapsed the unnecessary
appointments by over 8,000 a month, reduced customer complaints, reduced
the amount of time an RSA had to spend on the phone (because they didn’t
need to schedule so many appointments), and proven that the change didn’t
affect repair service levels one bit.