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

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 -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 Assumptions And Constraints

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