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.
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