NFor Earnest Koshi Li Ran Shen, Yi 11.06.2008

1. Application of 6-Sigma for Service Improvement Case Study: Mala Tang NFor Earnest Koshi Li Ran Shen, Yi 11.06.2008

2. Contents • Motivation, Goals and Expected Results • Define • CTQ • Process Description • Measure • Actual Process with Time • Questionnaire Survey • Analyze • Cause and Effect Chart • AHP Evaluation • Pareto Chart • Improve • Design of Experiments • Simulation • Conclusion

3. Motivation, Goals and Expected Results • Tsinghua University is a large community hence, need for improvement in on campus services systems in our campus • In this research project, we adopt DMAIC methodology for the improvement service quality of the Mala Tang window at the Taoli Yuan refectory which is one of biggest on campus • By applying six sigma, we seeks to find and eliminate causes of defects and errors in this sector by focusing on outputs that are critical to students who are the customers. • There exist long queues in the refectory during the rush hours , almost 40% of time in the refectory spent in queue. • Goal is to reduce the total waiting time to 7 minutes or even less while maintaining high level of customer satisfaction • Figure 2 below indicates the CTQs: diversity, waiting time and serving time. • We expect high diversity short waiting time and serving time t

4. Define - Critical to Quality Assumptions And Constraints -The queue is G/G/2 -FCFS criterion and Customers never abandon the queue -Infinite supply of spices -Total number of cook units in the Mala Tang window is six and 2 staffs -Limited accommodation limited and inventory storage space

5. Define - Process Description Variables -Decision variables: Include the process itself, proportion of ingredients and the layout -Independent variables or outputs: Directly or indirectly determined by the decision variables. Include average / maximum waiting time, average / maximum queue length, cost, and some subjective factors such as satisfaction of students

6. Measure – The ACTUAL Process .

7. Measure – The ACTUAL Process (cont…) Measurement -Video Analysis -Actions captured by use of a camera -Videos short secretly in order to get an authentic working conditions and without manipulation concerning motivation

8. Measure – Questionnaire Survey • Fifty copies distributed and forty seven valid returned • Aim of the survey was to detect the customers’ demand towards possible service and get their ratings for the service • Result provided opinion of customers permitting us to know what matters most • The next step will be to gather a high quantity of reasons which causes that long waiting / serving time

9. Measure – Questionnaire Survey (cont…)

10. Measure – Questionnaire Survey (cont…)

11. Analyze – Cause and Effect Chart

12. Analyze – AHP Evaluation .

13. Analyze – Pareto Chart Designed experiments Simulation

14. Improve – Design of Experiments

15. Improve – Design of Experiments (cont..)

16. Improve – Design of Experiments (cont..)

17. Improve – Simulation

18. Improve – Simulation (cont…) Service time as output

19. Improve – Simulation (cont…) Finished orders as output

20. Conclusion • Six Sigma was a useful method to identify the key factors of the service process • Standardization of the tasks, especially fixed task performing order and fewer occurances of unexpected tasks can give lower service time • Fewer branches in the process makes lower service time • refectories in general can raise their throughput

21. Conclusion • We did not match our defined goal, since variation on the customers’ side is still too high • service quality is improved by Six Sigma more customer requirements can be met, but not all • A revised application of Six Sigma should concentrate on customer behaviour and synchronize it with the process

22. Q & A Thank You Q & A