Six Sigma Case Study


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A simple, fun Six Sigma case study to explain the application of the DMAIC approach for process improvement and defect reduction.

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  • Dear was an interesting way to show application of Six Sigma concepts and i enjoyed your presentation......However what i disagree about is that for simple situations like improving late reaching to office.......i feel there are common sense improvement options for which you really don't need to do data analysis like DOE that you have shown.......yes it helped you to identify which is a better route based on data (longer or shorter etc.).........however the desired improvement, Z value can be obtained by adopting practices like early waking and finishing your errands either in previous evening etc and having a backup of cash etc.....which are mentioned in control plan.........somehow using such examples i feel we complicate the Six Sigma Subject and people start feeling it is a magic wand that will solve for everything and the true application is lost
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Six Sigma Case Study

  1. 1. a Six Sigma Case Study by XServe Consulting
  2. 2. Steve, Ronnie’s Manager, had earlier warned him on several occasions for coming late to office. This time, it was the FINAL Warning!!! RONNIE, You were late to work on 15 out of 26 Days in November. Treat this as my Final reminder to you. Steve (The Angry Boss) 2
  3. 3. Ronnie met his girlfriend Minnie for Dinner in the evening. Minnie assured an upset Ronnie that she will help him fix the problem. 3
  4. 4. Problem Statement In November 2013, Ronnie has been late to work on 15 out of 26 working days. Ronnie in Nov-2013 Reporting Time 10:30 AM Working Days 26 Defects (Late)* 15 Mean 10:35 AM Standard Deviation 00:12 DPMO 576,923 Z st 1.31 *Defect: Days when Ronnie reported to work after 10:30 AM 4
  5. 5. Let’s first look at the reasons for DELAY The Start Time: Delay at Home Early morning calls with Minnie Breakfast Waiting time for the Catching up with Morning News Elevator Deciding what Why do Wake up time to wear to work Day of the Week Other Causes Train Don’t feel like going to work Mode of Transport Car you get LATE to work? Route Taken Average speed Re-filling fuel in the morning 5
  6. 6. Reasons for Delay Root Cause Ronnie’s Vote Minnie’s Vote Final Verdict Wake-up time Almost the same everyday I agree. Your Good Morning messages seem to be automated No further analysis Catching up with Morning News Again, no change in schedule regardless of me reaching on time or late What’s in News anyways? No further analysis Breakfast Almost the same everyday It’s high time you watch your eating habits No further analysis What to wear to office Hardly matters I agree. Your wardrobe is another project in itself No further analysis Waiting time for the elevator Not much variation I agree No further analysis 6
  7. 7. Reasons for Delay Root Cause Early morning calls with Minnie Ronnie’s Vote Minnie’s Vote I guess we need to look at time spent on calls everyday Yes, if anything, the time has to increase. And it’s my call No further analysis everyday that wakes you up Mode of Transport – Have not used for Train months Car – Route Taken Average Speed Yes Final Verdict No further analysis There are three routes although I use two (A and B) The distance and traffic on each route Further analysis can impact your needed travel time Could be a reason I always tell you to be more careful while driving Further analysis needed 7
  8. 8. Reasons for Delay Root Cause Ronnie’s Vote Minnie’s Vote Re-filling of fuel in the morning I always re-fill while coming back from work Yes, while you are on your way to meet me. Hence, the No further analysis delays. This one was simple Day of the week Could be a factor as traffic density is higher on certain days I agree. Further analysis needed Don’t feel like going to work This is never the case. Zero absenteeism in 3 months That is because I asked you to save your leaves for our annual holiday No further analysis Final Verdict 8
  9. 9. Impact of Day of the Week on Ronnie’s Reporting Time Boxplot of Reporting Time  Test used: Analysis of Variance (ANOVA)  P-Value: 0.748  R-Square: 11.77%  Observation: There is no significant difference in Ronnie’s reporting time to work on different days of the week 9
  10. 10.  Minnie wanted to check the impact of selected route and average driving speed  As Ronnie did not have previous records of route and speed (although he preferred Route A as that was the shortest route), they set up a designed set of experiments with the following settings: Factor Route Taken Starting Time Average Speed Level (-1) A 09:50 AM 65 kph Level (+1) B 10:00 AM 75 kph 10
  11. 11. Given below is the DOE matrix that they set up. This is a 23 DOE with one replicate. Standard Order 12 9 11 16 4 14 2 15 3 13 10 1 7 6 8 5 Run Order Route 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 B A A B B B B A A A B A A B B A Average Speed Starting Time 75 65 75 75 75 65 65 75 75 65 65 65 75 65 75 65 09:50 09:50 09:50 10:00 09:50 10:00 09:50 10:00 09:50 10:00 09:50 09:50 10:00 10:00 10:00 10:00 11
  12. 12. Results of the Experiment P = 0.000 P = 0.136 P = 0.200 Although Route B is a slightly longer route (13.6 km compared to 12.7 km for Route A), the average travel time for Route B is less than 20 minutes. Average Speed (65 or 75) and Starting Time (09:50 am or 10:00 am) do not have a significant impact. 12
  13. 13. Ronnie’s Improvement Plan  Avoid using the shorter Route A  Always use Route B while going to work  Ensure to leave from home between 09:55 am and 10:00 am  Minnie also warned him against rash driving and asked him to maintain an average driving speed of 65 to 70 kph  They decided to record data for the next two weeks 13
  14. 14. Ronnie’s Improvement Measure Improve Reporting Time 10:30 AM 10:30 AM Working Days 26 12 Defects (Late)* 15 1 Mean 10:35 AM 10:17 AM Standard Deviation 00:12 00:07 DPMO 576,923 83,333 Z st 1.31 2.88  Improvement: From a DPMO of 576,923 to 83,333  Average reporting time: 10:17 am with just 1 defect out of 12 days 14
  15. 15. Minnie wanted 0 Defect Reporting time: 10:36 AM What went WRONG? Ronnie stopped at the ATM on his way to work as he had to pay his credit card bill. This could have been avoided if pre-planned. What else could go wrong? Ronnie needed a control plan. 15
  16. 16. Risk Assessment What can go Wrong? Delay in waking up as slept late (late night party, talking to Minnie, watching movie etc.) Daily errands (ATM, paying bills, buying cigarettes etc.) Severity Probability Risk Score (lower the better) (lower the better) (lower the better) 7 9 3 4 Action Plan 21 2 step wake up alarm system to be followed: Alarm call @ 08:00 am and call from Minnie @ 08:15 am 36 Bill pay schedule to be planned at the start of the month. Extra pack of cigarettes to be stored in the car. Emergency fund (Rs. 2000) to be stored in the office bag. Traffic Jams or slow moving traffic 9 3 27 Check for traffic updates while having breakfast on Android App and change route or leave early if necessary Flat Tyre 9 1 9 Low probability but check everyday after evening walk 16
  17. 17. Ronnie’s Improvement 17
  18. 18. Results Nov-2013 Dec-2013 Reporting Time 10:30 AM 10:30 AM Working Days 26 24 Defects (Late)* 15 1 Mean 10:35 AM 10:15 AM Standard Deviation 00:12 00:06 DPMO 576,923 41,667 Z st 1.31 3.23 Significant reduction in Defects (DPMO reduced from 576,923 to 41,667) & A Happy Boss 18
  19. 19. a Six Sigma Case Study by XServe Consulting
  20. 20. Questions Twitter Handle: XServeIn 20