A great presentation from the JSSS - Jacksonville Six Sigma Symposium, on variation and mistake proofing.

1. Continuous Process Improvement Variation and Mistake-Proofing

2. Variation & Mistake Proofing Upon completing this module, students should be able to: Understand common cause and special cause variation Understand how to interpret control charts Understand the Improvement Hierarchy Understand the concept of Mistake Proofing Recognize error-proofing in a process 2

3. Understanding Variation

4. Understanding Variation One of the most important concepts to understand in process improvement is variation. 4

5. Understanding Variation What does variation mean to customers? Variation means that a process does not produce the same result (the “Y”) every time. Variation directly affects the customer experience!!!. Customers “feel” the variation in a process… 5

6. Understanding Variation Why should we manage our process by measuring variation instead of averages? Customers feel the variation not the average! They feel this… …not this!!! 6

7. 7 Understanding Variation

8. 8 Types of Variation To successfully interpret variation, you must know the difference between: common cause variation & special cause variation. "If I had to reduce my message to management to just a few words, I'd say it all has to do with reducing variation.“ - W. Edwards Deming

10. It is produced by the interactions among the variables of the process.

12. This variation arises because of special circumstances.

13. Process improvement teams may work to mitigate or minimize special cause variation.

15. Trying to interpret individual occurrences of the process or toexplain the difference between those that are high and low. 10

17. Determine what was different when the special cause occurred.

19. Making fundamental changes in the process. 11

20. Visualizing Variation

21. UCL CL LCL Interpreting Control Charts A Control Chart is a tool we can use to identify types of variation. Point outside the limit 1. Run UCL 2. CL LCL UCL Trending 3. CL LCL 13

22. Interpreting Control Charts Approaching the center line UCL 4. CL LCL UCL Cycling (periodicity) 5. CL LCL UCL Approaching control limits 6. CL LCL 14

24. Seen as normal movement on the chart

25. Represent normal operation of the process (good or bad)

26. Improvement requires management action

27. Usually represents 85% of variability in a process

28. Special Cause (Assignable) Variation

29. Shown as “out of control” conditions

30. Represent abnormality in the process

31. Can be reduced or eliminated through local actions

32. Usually highly identifiable!!15

33. Variation Exercise Write the letter 'a' eight times… What do you see? Are they all identical? Why not? What caused the variation? - Pen used ? - Uneven paper ? - Caffeine level of the writer ? - Angle changed as you wrote ? What type of variation is this????? Would it make sense to circle one of the a's and ask: "Why is it different?" No! That particular 'a' is part of a system that includes all the reasons listed above (and more!). This is common cause variation. It is variation that is part of the system. Variation is inherent in all processes!

34. Variation Exercise Write 3 a's with your dominant hand, 3 more with your non-dominant hand, and then 2 more with your dominant hand.… What do you see? Are they all identical? Why not? What caused the variation this time? What type of variation is this????? Which ones are obviously different? You can circle the radically different a 's and say, "Something out of the ordinary occurred here!" (The answer is that you switched your hand.) This variation is called special cause variation.

35. Common Cause or Special Cause? Let’s examine the “not so simple” process of driving to work everyday What items can be classified as “common cause” variation and which items can we mark as special cause

36. Mistake Proofing(Poka-Yoke)

40. Impossible to Fail

41. Eliminate Activity

42. SPC

43. Certification & Audits

44. NotificationSimplification High chance that improvement will have lasting results! SPC Desirability Training Awareness Less chance that improvement will have lasting results! (Performance reverts to old habits.) 21

45. 22 Mistake-proofing defined: Using wisdom and ingenuity to create devices that allow you to do your job 100% defect free 100% of the time. Poke-yoke is a quality assurance technique developed by Japanese manufacturing engineer Shigeo Shingo. The aim of poke-yoke is to eliminate defects in a product by preventing or correcting mistakes as early as possible. Mistake-Proofing (Poke-Yoke)

47. Ground fault circuit breakers for bathroom inside or outside electric circuits

48. Pilotless gas ranges and hot water heaters

49. Child-proof caps on medicines

51. Air bags

52. Car engine warning lights23

53. Defects vs. Errors Y X 24

54. ┴ Mistake-Proof Function ┴ Mistake-Proofing States There are two states of a defect: ERROR HAS OCCURED ERROR ABOUT TO OCCUR DEFECT ERROR ABOUT TO OCCUR (Prediction) DEFECT HAS OCCCURRED (Detection) WARNING SIGNAL WARNING SIGNAL CONTROL/FEEDBACK CONTROL/FEEDBACK SHUTOWN SHUTOWN (Stop Operation) 25

56. A classic example of a prevention device is the design of a 3.5 inch computer diskette.

57. The diskette is carefully engineered to be slightly asymmetrical so that it will not fit into the disk drive in any orientation other than the correct one.

59. My microwave will not work if the door is open (a prevention device).

60. My car beeps if I leave the key in the ignition (a detection device).

62. Mistake-Proofing Hints to Help: Keep it Simple Inexpensive Give prompt feedback Give prompt action (prevention) Focused application Have the right people’s input Strive for the Best BEST: Make it impossible for errors BETTER: Allows for detection while an error is being made GOOD: Detects a defect before it continues to the next operation 29

64. When the load becomes too great, the circuit is broken.

65. Guide/reference/interference rod or pin

66. Template

67. Limit switch/micro-switch

68. Counter

69. Odd-part-out method

70. Sequence restriction

71. Standardize and solve

72. Critical condition indicator

73. Stopper/gate

74. SensorFloor sensors in moving shelf system prevent shelves from moving while person is in an aisle. 30

75. Implementing Mistake Proof Solutions Practical, Feasible, Cost-Effective: Before implementing a solution, it is always a good idea to conduct a reality check. You should assess whether the solution is practical, feasible, and cost effective. A cost-benefit analysis is one way of checking the cost-effectiveness. A benefit of mistaking-proofing is the elimination of risk. Compare the risk of NOT implementing the solution against the cost of implementing it. Always check with other areas you might affect!!!! 31

76. Implementing Mistake Proof Solutions Step 1: Use a Team Approach(a multi functional, diverse team) Step 2: Describe the Problem(clear, complete problem statement) Step 3: Interim Containment(Stabilize the current situation) Step 4: Define the Root Causes(what is the underlying reason for the defect?) Step 5: Develop (Mistake-Proofing) Solutions(Brainstorm, etc.) Step 6: Check for Practicality, Feasibility, & Cost Effectiveness Step 7: Implement the (Mistake-Proofing) Solution(Action Plan!) Step 8:Prevent Recurrence (Test/Monitor the solution to make sure it works) Step 9:Congratulate the Team(Make sure everyone celebrates!) Pilot! 32

77. Mistake Proofing Exercise A low clearance bridge has resulted in several instances of trucks getting damaged and wedged beneath the bridge. In the latest instance, the bridge, which carries railroad tracks across the road, ripped off the top of the truck, folding the metal like an accordion. Traffic was re-routed and crews were brought in to remove the truck. Police ticketed the driver for disobeying a traffic sign. The traffic sign warns drivers that the bridge is 11 feet above the pavement.

78. Mistake Proofing Exercise Use what you’ve learned about “error proofing” to develop a solution. What would you do to stop trucks from hitting this bridge? 10-15 Minutes Step 2: Describe the Problem(clear, complete problem statement) Step 3: Interim Containment(Stabilize the current situation) Step 4: Define the Root Causes(what is the underlying reason for the defect?) Step 5: Develop (Mistake-Proofing) Solutions(Brainstorm, etc.) Step 6: Check for Practicality, Feasibility, & Cost Effectiveness 34

80. (eliminates all possible defects?)

83. Project Questions Let’s talk about your projects: Problems you may be having What is going well? What is not going well? What difficulties have you encountered? Any other questions for us? 37