CHAPTER

1. CHAPTER 18 Waiting Lines

2. Disney World • Waiting in lines does not add enjoyment • Waiting in lines does not generate revenue Waiting lines are non-value added occurrences

3. Waiting Lines • Queuing theory: Mathematical approach to the analysis of waiting lines. • Goal of queuing analysis is to minimize the sum of two costs • Customer waiting costs • Service capacity costs • Waiting lines are non-value added occurrences

4. Implications of Waiting Lines • Cost to provide waiting space • Loss of business • Customers leaving • Customers refusing to wait • Loss of goodwill • Reduction in customer satisfaction • Congestion may disrupt other business operations

5. Queuing Analysis Figure 18.1 Total cost Customer waiting cost Capacity cost = + Total cost Cost Cost of service capacity Cost of customers waiting Service capacity Optimum

6. System Characteristics • Population Source • Infinite source: customer arrivals are unrestricted • Finite source: number of potential customers is limited • Number of observers (channels) • Arrival and service patterns • Queue discipline (order of service)

7. Processing order Arrivals Waiting line Service Exit System Elements of Queuing System Figure 18.2

8. Queuing Systems Figure 18.3 Multiple channel Multiple phase Channel: A server in a service system

9. Poisson Distribution Figure 18.4

10. Waiting line Models • Patient • Customers enter the waiting line and remain until served • Reneging • Waiting customers grow impatient and leave the line • Jockeying • Customers may switch to another line • Balking • Upon arriving, decide the line is too long and decide not to enter the line

11. Average number on time waiting in line 0 100% System Utilization Waiting Time vs. Utilization Figure 18.6

12. System Performance • Average number of customers waiting • Average time customers wait • System utilization • Implied cost • Probability that an arrival will have to wait Measured by:

13. Queuing Models: Infinite-Source • Single channel, exponential service time • Single channel, constant service time • Multiple channel, exponential service time • Multiple priority service, exponential service time

14. Processing order 1 3 2 1 1 Arrivals Waiting line Service Exit Arrivals are assigned a priority as they arrive System Priority Model

15. Service factor Average number waiting Average waiting time Average number running Average number being served Number in population Finite-Source Formulas Table 18.6

16. Not waiting or being served Being served Waiting J L H U W T Finite-Source Queuing

17. Other Approaches • Reduce perceived waiting time • Magazines in waiting rooms • Radio/television • In-flight movies • Filling out forms • Derive benefits from waiting • Place impulse items near checkout • Advertise other goods/services

18. Queuing QAP9 Managing Queues by Business Rules

19. Waiting Line Management DWL5 Disney Fast Pass Results/Distributing Queues

20. Pilot Queue System DWL6 Fast Pass at Disney’s Animal Kingdom—Statistics

21. Other Queue Perception Improvers DWL7 Disney World—Traditional Queue Improvement Methods