1. Managing Waiting Lines

3. Lines and Waiting
“Every day I get in the queue, that waits for the bus that takes me to you …”
Pete Townshend, Magic Bus

4. Where the Time Goes In a life time, the average American will spend--
SIX MONTHS
Waiting at stoplights
EIGHT MONTHS
Opening junk mail
ONE YEAR
Looking for misplaced 0bjects
Unsuccessfully returning
TWO YEARS phone calls
FOUR YEARS Doing housework
FIVE YEARS Waiting in line
SIX YEARS Eating

5. Cultural Attitudes
“Americans hate to wait. So business is trying a trick or two to make lines seem shorter…” The New York Times, September 25, 1988
“An Englishman, even when he is by himself, will form an orderly queue of one…” George Mikes, “How to be an Alien”
“In the Soviet Union, waiting lines were used as a rationing device…” Hedrick Smith, “The Russians”

6. Waiting Realities
Inevitability of Waiting: Waiting results from variations in arrival rates and service rates
Economics of Waiting: High utilization purchased at the price of customer waiting. Make waiting productive (salad bar) or profitable (drinking bar).

7. Laws of Service
Maister’s First Law: Customers compare expectations with perceptions.
Maister’s Second Law: Is hard to play catch-up ball.
Skinner’s Law: The other line always moves faster.
Jenkin’s Corollary: However, when you switch to another other line, the line you left moves faster.

8. Remember Me
I am the person who goes into a restaurant, sits down, and patiently waits while the wait-staff does everything but take my order.
I am the person that waits in line for the clerk to finish chatting with his buddy.
I am the one who never comes back and it amuses me to see money spent to get me back.
I was there in the first place, all you had to do was show me some courtesy and service The Customer

9. Psychology of Waiting
That Old Empty Feeling: Unoccupied time goes slowly
A Foot in the Door: Pre-service waits seem longer that in-service waits
The Light at the End of the Tunnel: Reduce anxiety with attention
Excuse Me, But I Was First: Social justice with FCFS queue discipline
They Also Serve, Who Sit and Wait: Avoids idle service capacity

10. Approaches to Controlling Customer Waiting
Animate: Disneyland distractions, elevator mirror, recorded music
Discriminate: Avis frequent renter treatment (out of sight)
Automate: Use computer scripts to address 75% of questions
Obfuscate: Disneyland staged waits (e.g. House of Horrors)

11. The Art of Service Recovery “To err is human; to recover, divine”
Measure Cost of Lost Customer
Listen Carefully
Anticipate Need for Recovery
Act Fast
Train Employees
Empower the Frontline
Inform Customers of Improvement

12. Essential Features of Queuing Systems
Renege
Arrival
process
Queue
discipline
Departure
Calling
population
Service
process
Queue
configuration
Balk
No future
need for
service

13. Arrival Process Arrival process Static Dynamic Random arrivals with
constant rate
Random arrival
rate varying
with time
Facility-
controlled
Customer-
exercised
control
Accept/Reject
Price
Appointments
Reneging
Balking

14. Distribution of Patient Interarrival Times

15. Temporal Variation in Arrival Rates

16. Poisson and Exponential Equivalence
Poisson distribution for number of arrivals per hour (top view)
One-hour
interval
Arrival Arrivals Arrivals Arrival
62 min.
40 min.
123 min.
Exponential distribution of time between arrivals in minutes (bottom view)

17. Queue Configurations Multiple Queue Single queue Take a Number Enter 34 2 8 6 10 12 7 11 9 5

18. Queue Discipline Queue discipline Static (FCFS rule) Dynamic selection
based on status
of queue
Selection based
on individual
customer
attributes
Number of
customers
waiting
Round robin
Priority
Preemptive
Processing time
of customers
(SPT rule)

19. Outpatient Service Process Distributions

20. Service Facility Arrangements
Service facility Server arrangement
Parking lot Self-serve
Cafeteria Servers in series
Toll booths Servers in parallel
Supermarket Self-serve, first stage; parallel servers, second stage
Hospital Many service centers in parallel and series, not all used by each patient

21. Topics for Discussion
Suggest some strategies for controlling variability in service times.
Suggest diversions that could make waiting less painful.
Select a bad and good waiting experience, and contrast the situations with respect to the aesthetics of the surroundings, diversions, people waiting, and attitude of servers.
Suggest ways that management can influence the arrival times of customers.
What are the benefits of a fast-food employee taking your order while waiting in line?

22. Interactive Exercise
The class breaks into small groups with at least one international student in each group, if possible. Based on overseas travel, each group reports on observations of waiting behavior from a cultural perspective.

24. Pronto Pizza
Draw a process flow diagram and identify the bottleneck operation.
Calculate the expected waiting time in the order preparation queue. Compare this value with your simulation result.
Use the ServiceModel computer simulation software and the Pronto.pkg file to determine the number of drivers that minimizes the total cost of salaries and guarantee discounts.

25. Pronto Pizza (cont.)
Based on your simulation recommended staffing level, what is the probability of paying off on the guarantee?
What do you think of this service guarantee policy?
What other design or operating suggestions could improve Pronto Pizza’s performance and customer service?